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1.  BRCA1 and BRCA2 mutations in central and southern Italian patients 
Breast Cancer Research : BCR  2000;2(4):307-310.
Protein truncation test (PTT) and single-strand conformation polymorphism (SSCP) assay were used to scan the BRCA1 and BRCA2 genes in 136 unrelated Italian breast/ovarian cancer patients. In the sample tested, BRCA1 and BRCA2 equally contributed to site-specific breast cancer patients who reported one to two breast cancer-affected first-/ second-degree relative(s) or who were diagnosed before age 40 years in the absence of a family history of breast/ovarian cancer. BRCA1 and BRCA2 mutations were mostly found in patients with disease diagnosis before and after age 50 years, respectively. Moreover, in cases with familial clustering of site-specific breast cancer, BRCA1 mostly accounted for tumours diagnosed before age 40 years and BRCA2 for tumours diagnosed after age 50 years. The BRCA1 and BRCA2 mutation spectrum was consistent with a lack of significant founder effects in the sample of patients studied.
Germline BRCA1 and BRCA2 mutations account for most hereditary breast/ovarian cancers and are associated with male breast cancer. Furthermore, constitutional mutations in these genes may occur in breast/ovarian cancer patients that do not meet stringent criteria of autosomal-dominant predisposition. The relevance of BRCA1 and BRCA2 mutations in such patients is still debated.
We sought to determine the impact of BRCA1 and BRCA2 mutations in a population of patients from central and southern Italy. We analyzed the BRCA1 and BRCA2 coding regions in 136 unrelated probands: 117 females with breast/ovarian cancer and 19 males with breast cancer. This population of patients was mostly representative of cases who are at risk for hereditary susceptibility, but who do not meet stringent criteria of autosomal-dominant predisposition.
Probands, subclassified as follows, were consecutively recruited depending on informed consent from patients attending breast cancer clinics in Rome and Naples. Selection criteria for females were as follows: breast cancer with breast cancer family history [one to two first-/second-degree relative(s), n = 55]; breast cancer diagnosed before age 40 years (no breast/ovarian cancer family history, n = 28); bilateral breast cancer (regardless of age and family history, n =10); breast cancer associated with gastrointestinal, pancreatic or uterine cancers [synchronous/metachronous or in first-degree relative(s), n = 9]; breast or ovarian cancer with family history of breast-ovarian/ovarian cancer (at least 1 first-/ second-degree relative, n = 10); and ovarian cancer with no breast/ovarian cancer family history (n = 5). Males with breast cancer were recruited regardless of age and family history. BRCA1 exon 11 and BRCA2 exons 10 and 11 were screened by PTT. Coding BRCA1 exons 2, 3, 5-10 and 12-24 and BRCA2 exons 2-9 and 12-27 were screened by SSCP. Primers are listed in Table 1. In 27 cases, analyzed by PTT along the entire BRCA1 coding sequence, BRCA1 SSCP analysis was limited to exons 2, 5, 20 and 24. Mutations were verified by sequence analysis on two independent blood samples.
Deleterious germline BRCA1/BRCA2 mutations were detected in 11 out of 136 cases (8%). Only three BRCA2 mutations were novel. One BRCA2 mutation recurred in two unrelated probands. Table 2 shows the mutations and data concerning carriers and their families. Table 3 shows correlations between BRCA1/BRCA2 mutations and sex, age at disease diagnosis and familial clustering of breast/ovarian cancer in the total patient population. Table 4 shows the proportions of BRCA1 and BRCA2 mutations in females with site-specific breast and breast-ovarian/ovarian cancer. Table 5 shows the frequency of BRCA1/BRCA2 mutations in males. BRCA1 and BRCA2 mutations, respectively, accounted for four out of 68 (6%) and one out of 68 (1%) cases diagnosed before age 50 years, and for one out of 68 (1%) and five out of 68 (7%) cases diagnosed after age 50 years. BRCA1 mutations were found in five out of 117 females (4%) and in none of 19 males (0%), and BRCA2 mutations were found in four out of 117 females (3%) and in two out of 19 males (10%). The proportions of BRCA1 and BRCA2 mutations coincided in site-specific female breast cancers (four out of 102; ie 4% each). BRCA1 and BRCA2 equally contributed to female breast cancers, with no familial clustering in those diagnosed before age 40 years (one out of 28; 4% each), and to female breast cancers, all ages, with familial clustering in one to two relatives (three out of 55; ie 5% each). In the latter subset of cases, BRCA1 mostly accounted for tumours diagnosed before age 40 years (two out of eight; 25%), and BRCA2 for tumours diagnosed after age 50 years (three out of 34; 9%). Regardless of family history, the respective contributions of BRCA1 and BRCA2 to site-specific female breast cancers diagnosed before age 40 years were 8% (three out of 36) and 3% (one out of 36). One BRCA1 mutation was detected among the 15 female probands from breast-ovarian/ovarian cancer families (7%). Among male breast cancers, BRCA2 mutations were identified in one out of five (20%) cases with family history and in one out of 14 (7%) apparently sporadic cases. No BRCA1 or BRCA2 mutations were found in female probands with nonfamilial bilateral breast cancer (10 cases) or in those with breast cancer associated with gastrointestinal, pancreatic or uterine cancers, synchronous/metachronous or in first-degree relative(s) (nine cases). These cases were all diagnosed after age 40 years.
Our results indicate a lack of relevant founder effects for BRCA1- and BRCA2-related disease in the sample of patients studied, which is consistent with other Italian studies and with ethnical and historical data. Overall, the contribution of BRCA1 and BRCA2 to breast/ovarian cancer in Italian patients appears to be less significant than in patients from communities with founder mutations. The present study is in agreement with direct estimates on other outbred populations, indicating that 7-10% of all female breast cancers that occur in patients aged under 40 years are due to BRCA1/BRCA2.
We found that BRCA1 and BRCA2 equally contributed to site-specific breast cancers who had one/two breast cancer-affected first-/second-degree relative(s) or who were diagnosed within age 40 years in the absence of family history. This is consistent with recent data that indicated that the respective frequencies of BRCA1 and BRCA2 mutations are comparable in early onset breast cancer. Considering the total population of patients analyzed here, however, BRCA1 and BRCA2 mutations were mostly found in cases with disease diagnosis before and after age 50 years, respectively. Moreover, in cases with familial clustering of site-specific breast cancer, BRCA1 mostly accounted for tumours diagnosed before age 40 years, and BRCA2 for tumours diagnosed after age 50 years. This is in agreement with a trend, which has been observed in other populations, for the proportion of cases with BRCA2 mutations to increase, and the proportion with mutations in BRCA1 to decrease, as the age at cancer onset increases.
As in other studies, the frequency of BRCA1/BRCA2 mutations taken together was lower than the estimated frequencies at comparable ages for all susceptibility alleles derived from the Contraceptive and Steroid Hormones (CASH) study. The discrepancy between direct data deriving from BRCA1/BRCA2 mutational analysis and CASH estimates could be due to several factors, including contribution of gene(s) other than BRCA1/BRCA2, differences between populations and relative insensitivity of mutational screening. Only BRCA1 mutations were found in breast/ovarian and site-specific ovarian cancer families. BRCA2, but not BRCA1 mutations were found in the male breast cancers. The overall proportion of males with BRCA2 mutations was high when compared with data from other studies on outbred populations, but was low compared with data from populations with founder effects.
The present results should be regarded as an approximation, because the following types of mutation are predicted to escape detection by the screening strategy used: mutations in noncoding regions; missense mutations within BRCA1 exon 11 and BRCA2 exons 10 and 11; large gene deletions; and mutations within the first and last 180 nucleotides of the amplicons analyzed by PTT.
PMCID: PMC13918  PMID: 11056688
BRCA1; BRCA2; breast; carcinoma; germline mutations; Italy
2.  Increased cell survival by inhibition of BRCA1 using an antisense approach in an estrogen responsive ovarian carcinoma cell line 
Breast Cancer Research  2000;2(2):139-148.
We tested the hypothesis that BRCA1 may play a role in the regulation of ovarian tumor cell death as well as the inhibition of ovarian cell proliferation. Introduction of BRCA1 antisense retroviral constructs into BG-1 estrogen-dependent ovarian adenocarcinoma cells resulted in reduced BRCA1 expression. BRCA1 antisense pooled populations and derived subclones were able to proliferate in monolayer culture without estrogen, whereas control cells began to die after 10 days of estrogen deprivation. In addition, both populations and subclones of BRCA1 antisense infected cells demonstrated a growth advantage in monolayer culture in the presence of estrogen and were able to proliferate in monolayer culture without estrogen, while control cells did not. Furthermore, clonal studies demonstrated that reduced levels of BRCA1 protein correlated with growth in soft agar and greater tumor formation in nude mice in the absence of estrogen. These data suggest that reduction of BRCA1 protein in BG-1 ovarian adenocarcinoma cells may have an effect on cell survival during estrogen deprivation both in vitro and in vivo.
Germline mutations in the breast and ovarian cancer susceptibility gene BRCA1, which is located on chromosome 17q21, are associated with a predisposition to the development of cancer in these organs [1,2]. No mutations in the BRCA1 gene have been detected in sporadic breast cancer cases, but mutations have been detected in sporadic cases of ovarian cancer [3,4]. Although there is debate regarding the level of cancer risk associated with mutations in BRCA1 and the significance of the lack of mutations in sporadic tumors, it is possible that alterations in the function of BRCA1 may occur by mechanisms other than mutation, leading to an underestimation of risk when it is calculated solely on the basis of mutational analysis. Such alterations cannot be identified until the function and regulation of BRCA1 are better understood.
The BRCA1 gene encodes a 220-kDa nuclear phosphoprotein that is regulated in response to DNA damaging agents [5,6,7] and in response to estrogen-induced growth [8,9,10,11]. Germline mutations that cause breast and ovarian cancer predisposition frequently result in truncated and presumably inactive BRCA1 protein [12].
BG-1 cells were derived from a patient with stage III, poorly differentiated ovarian adenocarcinoma [13]. This cell line, which expresses wild-type BRCA1, is estrogen responsive and withdrawal of estrogen results in eventual cell death. Previous studies suggest that BRCA1 is stimulated as a result of estrogen treatment [8,9,10,11], and also that BRCA1 may be involved in the cell death process [14]. Therefore, we examined the effect of reduction of BRCA1 levels in BG-1 cells on the cellular response to hormone depletion as well as estrogen stimulation. The results suggest that reduced levels of BRCA1 correlates with a survival advantage when BG-1 cells are placed under growth-restrictive and hormone-depleted conditions. In optimum growth conditions, significantly reduced levels of BRCA1 correlates with enhanced growth both in vitro and in vivo.
To test the hypothesis that BRCA1 may play a role in the regulation of ovarian tumor cell death as well as in the inhibition of ovarian cell proliferation.
Materials and methods:
The estrogen receptor-positive, BG-1 cell line [13], which contains an abundant amount of estrogen receptors (600 fmoles/100 μg DNA), was infected using a pLXSN retroviral vector (provided by AD Miller) containing an inverted partial human cDNA 900-base-pair sequence of BRCA1 (from nucleotide 121 in exon 1 to nucleotide 1025 in exon 11, accession #U14680). After 2 weeks of selection in 800 μg/ml of geneticin-G418 (Gibco/Life Technologies, Gaithersburg, MD, USA), BG-1 G418-resistant colonies were pooled, or individually isolated, and assayed for growth in the presence or absence of supplemented estrogen. Virally infected pooled populations of BG-1 cells were examined for BRCA1 message levels by ribonuclease protection assay (Fig. 1a). BRCA1 ribonuclease protection probe was made using an in vitro transcription kit (Ambion, Inc, Austin, TX, USA) as previously described [10] and derived clones were tested for protein levels by Western blot analysis using an anti-BRCA1 (Oncogene Research, Ab-1, Cambridge, MA, USA) antibody. Growth curve analysis of Infected populations and were pretreated for 5 days in phenol red-free, Dulbecco's modified eagle medium (DMEM)/F-12 medium (Gibco/Life Technologies) supplemented with 10% charcoal/dextran treated serum (Hyclone, Logan, UT, USA), then plated at 2.5 × 106 cells per 100mm dish in triplicate in the absence or presence of estrogen (10-8 mol/l; 17β-Estradiol; 1,3,5 (10) - Estratriene 3,17β-diol; Sigma, St Louis, MO, USA). For soft agar assay, clones were plated into 10 60-mm dishes at 1 × 105 cells/dish containing 0.3% bactopeptone agar with or without added estrogen (10-8 mol/l) in phenol red-free medium with 10% stripped serum in order to test for anchorage independent growth. BG-1 infected clones were tested for tumorigenicity by injection of cells (106 cells in 0.1cm2 50% matrigel; Collaborative Biomedical Products, Bedford, MA, USA) into subcutaneous sites in 6-week-old athymic Ncr-nude mice (NCI Animal Program, Bethesda, MD, USA) that were ovariectomized at approximately 4 weeks of age. Half of the ovariectomized mice received an implanted 0.18mg estrogen 60-day pellet (Innovative Research of America, Sarasota, FL, USA).
Antisense technology was effective in decreasing both RNA and protein levels of BRCA1 in the BG-1 human ovarian adenocarcinoma cells. BRCA1 antisense-infected populations contained significantly less BRCA1 message than control LXSN-infected pools and selected clones contained varying reduced levels of BRCA1 protein compared with control clones (Figs 1a and 1b).
Three independent BRCA1 antisense-infected cultures demonstrated a resistance to cell death induced by withdrawal from estrogen over a 6- to 20-day period (Fig. 2a). The BRCA1 antisense population also exhibited a threefold to sixfold increase in cell growth compared with control cells in the presence of estrogen treatment. BG-1 BRCA1 antisense clones demonstrated a similar response to pooled population studies, enhanced growth with estrogen, and failure to die upon estrogen depletion (Fig. 2b).
The BRCA1 antisense clones were further examined for other associated tumorigenic properties. All of the antisense clones were able to form colonies in soft agar (2-23 colonies per 104 cells plated; data not shown), whereas control clones were deficient in their ability to form colonies (0-0.8 colonies per 104 cells plated). Table 1 shows, in the presence of estrogen, the clone with the lowest levels of BRCA1 (AS-4) produced significantly more colonies (133 ± 17.9 colonies per 104 cells plated) than the control clone (NEO; 6 ± 3.1 colonies per 104 cells plated). Clones AS-4 and NEO were also injected with matrigel subcutaneously into ovariectomized athymic mice. Almost twice as many sites were positive for the AS-4 clone (14 out of 14) as for the NEO clone (eight out of 14) 42 days after injection. In addition, BRCA1 antisense tumors averaged twice the size of control tumors. The BRCA1 reduced cells also formed tumors with half the latency of control cells in the presence of implanted estrogen (11 days versus 21 days until tumor formation).
The present studies show that reduction in BRCA1 levels, using an antisense retroviral vector in the estrogen dependent BG-1 ovarian carcinoma cell line, contributes to confirmation of the hypothesis that BRCA1 plays a pivotal role in the balance between cell death and cell proliferation. BRCA1 RNA and protein levels were successfully reduced in populations and isolated clones of antisense infected BG-1 cells. Decreased BRCA1 levels rescued the BG-1 cells from growth arrest or cell death in adverse growth conditions in monolayer or soft agar conditions. Furthermore, a BRCA1 antisense clone that had significantly low levels of BRCA1 protein was able to form twice as many tumors in ovariectomized nude mice with a decreased latency compared with a control clone.
In multicellular mammalian organisms, a balance between cell proliferation and cell death is extremely important for the maintenance of normal healthy tissues. In support of this hypothesis, it has been shown that p53 and BRCA1 can form stable complexes, and can coactivate p21 and bax genes, which may lead to the activation of the apoptosis pathway [15]. The present data, which show that cells with a reduction of BRCA1 have a survival advantage in conditions where control cells fail to thrive, also supports this hypothesis. BRCA1 levels appear to affect the ability of cells to arrest growth or die in the absence of estrogenic growth-inducing conditions. Although mutations in this gene are uncommon in sporadic breast and ovarian tumors, BRCA1 expression levels and protein levels have been found to be reduced in sporadic human breast carcinomas [16,17,18,19]. In addition it has been demonstrated [20] that hormone-dependent tumors such as breast and ovarian cancers have a decreased ability to undergo apoptosis. Other mechanisms involving gene regulation may allow for decreased expression of BRCA1 in sporadic tumors. The response of BRCA1 mRNA and protein levels to mitogens and hormones in vitro suggests that BRCA1 may play a role in regulation of cell growth or maintenance [21]. The BRCA1 gene product may be involved in the regulation of hormone response pathways, and the present results demonstrate that loss of BRCA1 may result in loss of inhibitory control of these mitogenic pathways. These studies show that reduction in BRCA1 mRNA and protein can result in increased proliferation of BG-1 ovarian cancer cells in both in vitro and in vivo conditions, suggesting that BRCA1 may normally be acting as a growth inhibitor. Low BRCA1 levels found in sporadic cancers may be an important factor in tumorigenesis. The present data suggest that diminished levels of BRCA1 not only accelerate proliferation in the BG-1 ovarian carcinoma cell line, but also appear to promote tumorigenesis. We propose that the loss or reduction of BRCA1 may predispose a cell population to neoplastic transformation by altering the balance between cell death and proliferation/survival, rendering it more sensitive to secondary genetic changes.
PMCID: PMC13916  PMID: 11056686
antisense; BRCA1; cell death; estrogen; ovarian cancer; proliferation
3.  Use of DNA–Damaging Agents and RNA Pooling to Assess Expression Profiles Associated with BRCA1 and BRCA2 Mutation Status in Familial Breast Cancer Patients 
PLoS Genetics  2010;6(2):e1000850.
A large number of rare sequence variants of unknown clinical significance have been identified in the breast cancer susceptibility genes, BRCA1 and BRCA2. Laboratory-based methods that can distinguish between carriers of pathogenic mutations and non-carriers are likely to have utility for the classification of these sequence variants. To identify predictors of pathogenic mutation status in familial breast cancer patients, we explored the use of gene expression arrays to assess the effect of two DNA–damaging agents (irradiation and mitomycin C) on cellular response in relation to BRCA1 and BRCA2 mutation status. A range of regimes was used to treat 27 lymphoblastoid cell-lines (LCLs) derived from affected women in high-risk breast cancer families (nine BRCA1, nine BRCA2, and nine non-BRCA1/2 or BRCAX individuals) and nine LCLs from healthy individuals. Using an RNA–pooling strategy, we found that treating LCLs with 1.2 µM mitomycin C and measuring the gene expression profiles 1 hour post-treatment had the greatest potential to discriminate BRCA1, BRCA2, and BRCAX mutation status. A classifier was built using the expression profile of nine QRT–PCR validated genes that were associated with BRCA1, BRCA2, and BRCAX status in RNA pools. These nine genes could distinguish BRCA1 from BRCA2 carriers with 83% accuracy in individual samples, but three-way analysis for BRCA1, BRCA2, and BRCAX had a maximum of 59% prediction accuracy. Our results suggest that, compared to BRCA1 and BRCA2 mutation carriers, non-BRCA1/2 (BRCAX) individuals are genetically heterogeneous. This study also demonstrates the effectiveness of RNA pools to compare the expression profiles of cell-lines from BRCA1, BRCA2, and BRCAX cases after treatment with irradiation and mitomycin C as a method to prioritize treatment regimes for detailed downstream expression analysis.
Author Summary
A large number of rare sequence variants of unknown clinical significance have been identified in the breast cancer susceptibility genes, BRCA1 and BRCA2. Laboratory methods to identify which of these variants are mutations would have utility for counseling and clinical decision making when identified in patients with a family history of breast cancer. We used DNA–damaging agents to disturb gene expression profiles of cell-lines derived from blood of patients, and we compared patterns from women with BRCA1 and BRCA2 mutations to women familial breast cancer families without such mutations. Using a pooling strategy, which allowed us to compare several treatments at one time, we identified which treatment caused the greatest difference in gene-expression changes between patient groups and used this treatment method for further study. We were able to accurately classify BRCA1 and BRCA2 samples, and our results supported other reported findings that suggested familial breast cancer patients without BRCA1/2 mutations are genetically heterogeneous. We demonstrate a useful strategy to identify treatments that induce gene expression differences associated with BRCA1/2 mutation status. This strategy may aid the development of a molecular-based tool to screen individuals from multi-case breast cancer families for the presence of pathogenic mutations.
PMCID: PMC2824809  PMID: 20174566
4.  Selected Aspects of Molecular Diagnostics of Constitutional Alterations in BRCA1 and BRCA2 Genes Associated with Increased Risk of Breast Cancer in the Polish Population 
This study was undertaken to determine: 1) Type and prevalence of founder mutations BRCA1 and BRCA2 genes in Polish families with strong aggregation of breast and/or ovarian cancer. 2) Risk of breast and/or ovarian cancer depending on type of BRCA1 gene mutation. 3) Prevalence of BRCA1 mutation and of other alleles presumably linked with predisposition to breast cancer in unselected Polish patients with breast cancer. 4) Risk of breast cancer in patients with 5972C/T polymorphism that alters the BRCA2 protein structure.
Summary of the results
1. Among 66 families from several regions in Poland with a strong aggregation of breast/ovarian cancer, founder mutation of the BRCA1 gene were disclosed in 34 families and of the BRCA2 gene in on family. Altogether, seven different mutations were disclosed. Five mutations were found in at least two families in this group. The most frequent mutation was 5382insC (18 families), followed by C61G (7 families) and 4153delA (4 families). 2. Among 200 families representative for Poland with strong aggregation of breast/ovarian cancer, mutation of the BRCA1 gene were found in 122 families (61%) and of the BRCA2 gene in seven families (3,5%). 119 out of 122 mutations of the BRCA1 gene (97,5%) were repeatable. Three recurrent mutations of the BRCA1 gene (5382insC, C61G, 4153delA) characteristic for the Polish population were disclosed in 111 families representing 86% of all pathogenic sequences of this gene. 3. The risk of ovarian cancer in carriers of the three most frequent recurrent mutation of the BRCA1 gene in Poland is similar (OR 43.6 for 5382insC and 50 for 4153delA). The risk of breast cancer is significantly different for 4153delA (OR 1) and for other mutations (OR 10.9). 4. Among 2012 unselected breast cancers diagnosed in hospitals of nine Polish cities, mutations of the BRCA1 gene (5382insC, C61G, 4153delA) were disclosed in 2.9% patients. CHEK2 alternation (1100delC, IVS2+1G>A, I157T) was discovered in 8.1% and NBS1 mutation (657del5) in 0.8% of the patients. The changes were more frequent in the study than the control group. However, the risk of breast cancer was significantly higher for only three of them. Two changes, namely 5382insC and C61G of the BRCA1 gene revealed a high penetrance (OR 6.2 and 15.0, respectively), while I157T of the CHEK2 gene was associated with a low risk of breast cancer (OR 1.4). Mutations of the BRCA1, CHEK2 and NSB1 genes were significantly more frequent in patients with breast cancer diagnosed prior to 50 years of age. The mean age at diagnosis was 47.2 years for carriers of the BRCA1 mutation, 50.7 years for NBS1 and 54.2 for CHEK2. The mean age at diagnosis in the group of patients without any if the mutations described above was 56.1 years. When breast cancer patients with the diagnosis before and after 50 years of age were compared, the greatest difference in the frequency of mutation was revealed for the BRCA1 gene (5.5% vs 1.5%).
BRCA1 mutations were significantly more frequent I familial aggregates of the tumor (10.8%), but were also present in sporadic cases (1.8%). For the CHEK2 and NBS1 genes, there was no correlation between frequency and family history of cancer in probands. 5. A higher frequency of heterozygous carriers of 5972C/T polymorphism of the BRCA2 gene was demonstrated for breast cancer prior to 50 years of age (OR 1.4). the risk of breast cancer prior to 50 years of age was particularly high in 5972T/T homozygote (OR 4.7). This polymorphism was associated with breast cancer notable for intraductal growth.
1. Efficient molecular diagnostics of genetic predisposition to breast/ovarian cancer in Poland could be based on relatively simple tests disclosing some of the most frequent recurrent mutations of the BRCA1 gene. 2. The risk of breast cancer seems to be only slightly higher in carriers of some BRCA1 gene mutations. This finding should be taken into account during work on prevention schemes for carriers of the BRCA1 mutations. 3. 5382insC and C61G mutations of the BRCA1 gene are linked with high risk of breast cancer. Changes in the CHEK2 and NBS1 genes appear to be linked with a higher risk of breast cancers, particularly at young age. However, penetrance in this case is low. All patients with breast cancer should be tested for BRCA1 gene mutations because the percentage of mutations is also high in patients older than 50 years of age or without familiar aggregation of breast/ovarian cancer. 4. Polymorphic changes in the BRCA2 gene sequence previously regarded as non-pathogenic may nevertheless predispose, homozygotes in particular, to breast cancer. Apparently, the recessive character of these changes is responsible for the negative family history in most cases. The use of DNA tests is the only way to disclose increased risk of breast cancer in carriers of the 5972T/T mutation.
PMCID: PMC4177211  PMID: 20223018
breast cancer; ovarian cancer; inherited predisposition; BRCA1; BRCA2
5.  Cancer Screening with Digital Mammography for Women at Average Risk for Breast Cancer, Magnetic Resonance Imaging (MRI) for Women at High Risk 
Executive Summary
The purpose of this review is to determine the effectiveness of 2 separate modalities, digital mammography (DM) and magnetic resonance imaging (MRI), relative to film mammography (FM), in the screening of women asymptomatic for breast cancer. A third analysis assesses the effectiveness and safety of the combination of MRI plus mammography (MRI plus FM) in screening of women at high risk. An economic analysis was also conducted.
Research Questions
How does the sensitivity and specificity of DM compare to FM?
How does the sensitivity and specificity of MRI compare to FM?
How do the recall rates compare among these screening modalities, and what effect might this have on radiation exposure? What are the risks associated with radiation exposure?
How does the sensitivity and specificity of the combination of MRI plus FM compare to either MRI or FM alone?
What are the economic considerations?
Clinical Need
The effectiveness of FM with respect to breast cancer mortality in the screening of asymptomatic average- risk women over the age of 50 has been established. However, based on a Medical Advisory Secretariat review completed in March 2006, screening is not recommended for women between the ages of 40 and 49 years. Guidelines published by the Canadian Task Force on Preventive Care recommend mammography screening every 1 to 2 years for women aged 50 years and over, hence, the inclusion of such women in organized breast cancer screening programs. In addition to the uncertainty of the effectiveness of mammography screening from the age of 40 years, there is concern over the risks associated with mammographic screening for the 10 years between the ages of 40 and 49 years.
The lack of effectiveness of mammography screening starting at the age of 40 years (with respect to breast cancer mortality) is based on the assumption that the ability to detect cancer decreases with increased breast tissue density. As breast density is highest in the premenopausal years (approximately 23% of postmenopausal and 53% of premenopausal women having at least 50% of the breast occupied by high density), mammography screening is not promoted in Canada nor in many other countries for women under the age of 50 at average risk for breast cancer. It is important to note, however, that screening of premenopausal women (i.e., younger than 50 years of age) at high risk for breast cancer by virtue of a family history of cancer or a known genetic predisposition (e.g., having tested positive for the breast cancer genes BRCA1 and/or BRCA2) is appropriate. Thus, this review will assess the effectiveness of breast cancer screening with modalities other than film mammography, specifically DM and MRI, for both pre/perimenopausal and postmenopausal age groups.
International estimates of the epidemiology of breast cancer show that the incidence of breast cancer is increasing for all ages combined whereas mortality is decreasing, though at a slower rate. The observed decreases in mortality rates may be attributable to screening, in addition to advances in breast cancer therapy over time. Decreases in mortality attributable to screening may be a result of the earlier detection and treatment of invasive cancers, in addition to the increased detection of ductal carcinoma in situ (DCIS), of which certain subpathologies are less lethal. Evidence from the Surveillance, Epidemiology and End Results (better known as SEER) cancer registry in the United States, indicates that the age-adjusted incidence of DCIS has increased almost 10-fold over a 20 year period, from 2.7 to 25 per 100,000.
There is a 4-fold lower incidence of breast cancer in the 40 to 49 year age group than in the 50 to 69 year age group (approximately 140 per 100,000 versus 500 per 100,000 women, respectively). The sensitivity of FM is also lower among younger women (approximately 75%) than for women aged over 50 years (approximately 85%). Specificity is approximately 80% for younger women versus 90% for women over 50 years. The increased density of breast tissue in younger women is likely responsible for the decreased accuracy of FM.
Treatment options for breast cancer vary with the stage of disease (based on tumor size, involvement of surrounding tissue, and number of affected axillary lymph nodes) and its pathology, and may include a combination of surgery, chemotherapy and/or radiotherapy. Surgery is the first-line intervention for biopsy-confirmed tumors. The subsequent use of radiation, chemotherapy or hormonal treatments is dependent on the histopathologic characteristics of the tumor and the type of surgery. There is controversy regarding the optimal treatment of DCIS, which is considered a noninvasive tumour.
Women at high risk for breast cancer are defined as genetic carriers of the more commonly known breast cancer genes (BRCA1, BRCA2 TP53), first degree relatives of carriers, women with varying degrees of high risk family histories, and/or women with greater than 20% lifetime risk for breast cancer based on existing risk models. Genetic carriers for this disease, primarily women with BRCA1 or BRCA2 mutations, have a lifetime probability of approximately 85% of developing breast cancer. Preventive options for these women include surgical interventions such as prophylactic mastectomy and/or oophorectomy, i.e., removal of the breasts and/or ovaries. Therefore, it is important to evaluate the benefits and risks of different screening modalities, to identify additional options for these women.
This Medical Advisory Secretariat review is the second of 2 parts on breast cancer screening, and concentrates on the evaluation of both DM and MRI relative to FM, the standard of care. Part I of this review (March 2006) addressed the effectiveness of screening mammography in 40 to 49 year old average-risk women. The overall objective of the present review is to determine the optimal screening modality based on the evidence.
Evidence Review Strategy
The Medical Advisory Secretariat followed its standard procedures and searched the following electronic databases: Ovid MEDLINE, EMBASE, Ovid MEDLINE In-Process & Other Non-Indexed Citations, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews and The International Network of Agencies for Health Technology Assessment database. The subject headings and keywords searched included breast cancer, breast neoplasms, mass screening, digital mammography, magnetic resonance imaging. The detailed search strategies can be viewed in Appendix 1.
Included in this review are articles specific to screening and do not include evidence on diagnostic mammography. The search was further restricted to English-language articles published between January 1996 and April 2006. Excluded were case reports, comments, editorials, nonsystematic reviews, and letters.
Digital Mammography: In total, 224 articles specific to DM screening were identified. These were examined against the inclusion/exclusion criteria described below, resulting in the selection and review of 5 health technology assessments (HTAs) (plus 1 update) and 4 articles specific to screening with DM.
Magnetic Resonance Imaging: In total, 193 articles specific to MRI were identified. These were examined against the inclusion/exclusion criteria described below, resulting in the selection and review of 2 HTAs and 7 articles specific to screening with MRI.
The evaluation of the addition of FM to MRI in the screening of women at high risk for breast cancer was also conducted within the context of standard search procedures of the Medical Advisory Secretariat. as outlined above. The subject headings and keywords searched included the concepts of breast cancer, magnetic resonance imaging, mass screening, and high risk/predisposition to breast cancer. The search was further restricted to English-language articles published between September 2007 and January 15, 2010. Case reports, comments, editorials, nonsystematic reviews, and letters were not excluded.
MRI plus mammography: In total, 243 articles specific to MRI plus FM screening were identified. These were examined against the inclusion/exclusion criteria described below, resulting in the selection and review of 2 previous HTAs, and 1 systematic review of 11 paired design studies.
Inclusion Criteria
English-language articles, and English or French-language HTAs published from January 1996 to April 2006, inclusive.
Articles specific to screening of women with no personal history of breast cancer.
Studies in which DM or MRI were compared with FM, and where the specific outcomes of interest were reported.
Randomized controlled trials (RCTs) or paired studies only for assessment of DM.
Prospective, paired studies only for assessment of MRI.
Exclusion Criteria
Studies in which outcomes were not specific to those of interest in this report.
Studies in which women had been previously diagnosed with breast cancer.
Studies in which the intervention (DM or MRI) was not compared with FM.
Studies assessing DM with a sample size of less than 500.
Digital mammography.
Magnetic resonance imaging.
Screening with film mammography.
Outcomes of Interest
Breast cancer mortality (although no studies were found with such long follow-up).
Recall rates.
Summary of Findings
Digital Mammography
There is moderate quality evidence that DM is significantly more sensitive than FM in the screening of asymptomatic women aged less than 50 years, those who are premenopausal or perimenopausal, and those with heterogeneously or extremely dense breast tissue (regardless of age).
It is not known what effect these differences in sensitivity will have on the more important effectiveness outcome measure of breast cancer mortality, as there was no evidence of such an assessment.
Other factors have been set out to promote DM, for example, issues of recall rates and reading and examination times. Our analysis did not show that recall rates were necessarily improved in DM, though examination times were lower than for FM. Other factors including storage and retrieval of screens were not the subject of this analysis.
Magnetic Resonance Imaging
There is moderate quality evidence that the sensitivity of MRI is significantly higher than that of FM in the screening of women at high risk for breast cancer based on genetic or familial factors, regardless of age.
Radiation Risk Review
Cancer Care Ontario conducted a review of the evidence on radiation risk in screening with mammography women at high risk for breast cancer. From this review of recent literature and risk assessment that considered the potential impact of screening mammography in cohorts of women who start screening at an earlier age or who are at increased risk of developing breast cancer due to genetic susceptibility, the following conclusions can be drawn:
For women over 50 years of age, the benefits of mammography greatly outweigh the risk of radiation-induced breast cancer irrespective of the level of a woman’s inherent breast cancer risk.
Annual mammography for women aged 30 – 39 years who carry a breast cancer susceptibility gene or who have a strong family breast cancer history (defined as a first degree relative diagnosed in their thirties) has a favourable benefit:risk ratio. Mammography is estimated to detect 16 to 18 breast cancer cases for every one induced by radiation (Table 1). Initiation of screening at age 35 for this same group would increase the benefit:risk ratio to an even more favourable level of 34-50 cases detected for each one potentially induced.
Mammography for women under 30 years of age has an unfavourable benefit:risk ratio due to the challenges of detecting cancer in younger breasts, the aggressiveness of cancers at this age, the potential for radiation susceptibility at younger ages and a greater cumulative radiation exposure.
Mammography when used in combination with MRI for women who carry a strong breast cancer susceptibility (e.g., BRCA1/2 carriers), which if begun at age 35 and continued for 35 years, may confer greatly improved benefit:risk ratios which were estimated to be about 220 to one.
While there is considerable uncertainty in the risk of radiation-induced breast cancer, the risk expressed in published studies is almost certainly conservative as the radiation dose absorbed by women receiving mammography recently has been substantially reduced by newer technology.
A CCO update of the mammography radiation risk literature for 2008 and 2009 gave rise to one article by Barrington de Gonzales et al. published in 2009 (Barrington de Gonzales et al., 2009, JNCI, vol. 101: 205-209). This article focuses on estimating the risk of radiation-induced breast cancer for mammographic screening of young women at high risk for breast cancer (with BRCA gene mutations). Based on an assumption of a 15% to 25% or less reduction in mortality from mammography in these high risk women, the authors conclude that such a reduction is not substantially greater than the risk of radiation-induced breast cancer mortality when screening before the age of 34 years. That is, there would be no net benefit from annual mammographic screening of BRCA mutation carriers at ages 25-29 years; the net benefit would be zero or small if screening occurs in 30-34 year olds, and there would be some net benefit at age 35 years or older.
The Addition of Mammography to Magnetic Resonance Imaging
The effects of the addition of FM to MRI screening of high risk women was also assessed, with inclusion and exclusion criteria as follows:
Inclusion Criteria
English-language articles and English or French-language HTAs published from September 2007 to January 15, 2010.
Articles specific to screening of women at high risk for breast cancer, regardless of the definition of high risk.
Studies in which accuracy data for the combination of MRI plus FM are available to be compared to that of MRI and FM alone.
RCTs or prospective, paired studies only.
Studies in which women were previously diagnosed with breast cancer were also included.
Exclusion Criteria
Studies in which outcomes were not specific to those of interest in this report.
Studies in which there was insufficient data on the accuracy of MRI plus FM.
Both MRI and FM.
Screening with MRI alone and FM alone.
Outcomes of Interest
Summary of Findings
Magnetic Resonance Imaging Plus Mammography
Moderate GRADE Level Evidence that the sensitivity of MRI plus mammography is significantly higher than that of MRI or FM alone, although the specificity remains either unchanged or decreases in the screening of women at high risk for breast cancer based on genetic/familial factors, regardless of age.
These studies include women at high risk defined as BRCA1/2 or TP53 carriers, first degree relatives of carriers, women with varying degrees of high risk family histories, and/or >20% lifetime risk based on existing risk models. This definition of high risk accounts for approximately 2% of the female adult population in Ontario.
PMCID: PMC3377503  PMID: 23074406
6.  Seventeen years after BRCA1: what is the BRCA mutation status of the breast cancer patients in Africa? – a systematic review 
SpringerPlus  2012;1(1):83.
With the discovery of the BRCA1 gene and other genetic mutations associated with breast cancer, it has been established that hereditary mutations account for up to 5% of patients presenting with breast cancer.
We performed a systematic review of English Language Literature to determine the role of BRCA1 and BRCA2 gene mutations in African breast cancer patients. PUBMED and AJOL database were searched for publications addressing Breast Cancer and BRCA1 and BRCA2 genes. PUBMED was searched using the following words in various combinations; ‘Breast Cancer’, ‘BRCA1’, ‘BRCA2’, ‘BRCA’, ‘Genes’, ‘Cancer Genes’, and ‘Africa’.
16 studies fulfilled the study criteria up till December 2011. The studies were from North Africa (NA) and Sub-Saharan Africa (SSA).
A total of 9 studies were found evaluating 752 (352 repeated Zhang J (2010)) patients from SSA. Three studies (144 patients) evaluated all the coding regions of both BRCA1 and BRCA2 while 2 studies (571 patients) evaluated part(s) of BRCA1 and one (20 Patients) evaluated part(s) of BRCA2, one re-evaluated the whole of the BRCA1 gene in a previous sub-set of patients, while one (16 patients) evaluated parts of both BRCA1 and BRCA2.
In North Africa, 6 studies evaluated 374 patients, with 4 studies (219 patients) evaluating the whole of the BRCA1 and BRCA2 genes while two (155 patients) studies evaluated only parts of both BRCA1 and BRCA2, with one of the studies evaluating the whole of the BRCA1 gene in a subset (24 patients).
Due to this paucity of well powered population based studies evaluating the influence of BRCA genetic mutations in breast cancer patients in Africa, there is a need to perform well powered studies and population screening to determine the impact of germ line mutations in the Breast Cancer patient in Africa before any categorical statements can be made with respect to their BRCA status.
PMCID: PMC3600121  PMID: 23519070
Breast cancer; Gene mutations; Africa; BRCA1; BRCA2; Systematic review
7.  Targeted Prostate Cancer Screening in BRCA1 and BRCA2 Mutation Carriers: Results from the Initial Screening Round of the IMPACT Study 
Bancroft, Elizabeth K. | Page, Elizabeth C. | Castro, Elena | Lilja, Hans | Vickers, Andrew | Sjoberg, Daniel | Assel, Melissa | Foster, Christopher S. | Mitchell, Gillian | Drew, Kate | Mæhle, Lovise | Axcrona, Karol | Evans, D. Gareth | Bulman, Barbara | Eccles, Diana | McBride, Donna | van Asperen, Christi | Vasen, Hans | Kiemeney, Lambertus A. | Ringelberg, Janneke | Cybulski, Cezary | Wokolorczyk, Dominika | Selkirk, Christina | Hulick, Peter J. | Bojesen, Anders | Skytte, Anne-Bine | Lam, Jimmy | Taylor, Louise | Oldenburg, Rogier | Cremers, Ruben | Verhaegh, Gerald | van Zelst-Stams, Wendy A. | Oosterwijk, Jan C. | Blanco, Ignacio | Salinas, Monica | Cook, Jackie | Rosario, Derek J. | Buys, Saundra | Conner, Tom | Ausems, Margreet G. | Ong, Kai-ren | Hoffman, Jonathan | Domchek, Susan | Powers, Jacquelyn | Teixeira, Manuel R. | Maia, Sofia | Foulkes, William D. | Taherian, Nassim | Ruijs, Marielle | den Enden, Apollonia T. Helderman-van | Izatt, Louise | Davidson, Rosemarie | Adank, Muriel A. | Walker, Lisa | Schmutzler, Rita | Tucker, Kathy | Kirk, Judy | Hodgson, Shirley | Harris, Marion | Douglas, Fiona | Lindeman, Geoffrey J. | Zgajnar, Janez | Tischkowitz, Marc | Clowes, Virginia E. | Susman, Rachel | Ramón y Cajal, Teresa | Patcher, Nicholas | Gadea, Neus | Spigelman, Allan | van Os, Theo | Liljegren, Annelie | Side, Lucy | Brewer, Carole | Brady, Angela F. | Donaldson, Alan | Stefansdottir, Vigdis | Friedman, Eitan | Chen-Shtoyerman, Rakefet | Amor, David J. | Copakova, Lucia | Barwell, Julian | Giri, Veda N. | Murthy, Vedang | Nicolai, Nicola | Teo, Soo-Hwang | Greenhalgh, Lynn | Strom, Sara | Henderson, Alex | McGrath, John | Gallagher, David | Aaronson, Neil | Ardern-Jones, Audrey | Bangma, Chris | Dearnaley, David | Costello, Philandra | Eyfjord, Jorunn | Rothwell, Jeanette | Falconer, Alison | Gronberg, Henrik | Hamdy, Freddie C. | Johannsson, Oskar | Khoo, Vincent | Kote-Jarai, Zsofia | Lubinski, Jan | Axcrona, Ulrika | Melia, Jane | McKinley, Joanne | Mitra, Anita V. | Moynihan, Clare | Rennert, Gad | Suri, Mohnish | Wilson, Penny | Killick, Emma | Moss, Sue | Eeles, Rosalind A.
European Urology  2014;66(3):489-499.
Men with germline breast cancer 1, early onset (BRCA1) or breast cancer 2, early onset (BRCA2) gene mutations have a higher risk of developing prostate cancer (PCa) than noncarriers. IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls) is an international consortium of 62 centres in 20 countries evaluating the use of targeted PCa screening in men with BRCA1/2 mutations.
To report the first year's screening results for all men at enrolment in the study.
Design, setting and participants
We recruited men aged 40–69 yr with germline BRCA1/2 mutations and a control group of men who have tested negative for a pathogenic BRCA1 or BRCA2 mutation known to be present in their families. All men underwent prostate-specific antigen (PSA) testing at enrolment, and those men with PSA >3 ng/ml were offered prostate biopsy.
Outcome measurements and statistical analysis
PSA levels, PCa incidence, and tumour characteristics were evaluated. The Fisher exact test was used to compare the number of PCa cases among groups and the differences among disease types.
Results and limitations
We recruited 2481 men (791 BRCA1 carriers, 531 BRCA1 controls; 731 BRCA2 carriers, 428 BRCA2 controls). A total of 199 men (8%) presented with PSA >3.0 ng/ml, 162 biopsies were performed, and 59 PCas were diagnosed (18 BRCA1 carriers, 10 BRCA1 controls; 24 BRCA2 carriers, 7 BRCA2 controls); 66% of the tumours were classified as intermediate- or high-risk disease. The positive predictive value (PPV) for biopsy using a PSA threshold of 3.0 ng/ml in BRCA2 mutation carriers was 48%—double the PPV reported in population screening studies. A significant difference in detecting intermediate- or high-risk disease was observed in BRCA2 carriers. Ninety-five percent of the men were white, thus the results cannot be generalised to all ethnic groups.
The IMPACT screening network will be useful for targeted PCa screening studies in men with germline genetic risk variants as they are discovered. These preliminary results support the use of targeted PSA screening based on BRCA genotype and show that this screening yields a high proportion of aggressive disease.
Patient summary
In this report, we demonstrate that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these men resulted in the identification of tumours that were more likely to require treatment.
Take Home Message
This report demonstrates that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these higher-risk men resulted in the identification of tumours that were more likely to require treatment.
PMCID: PMC4105321  PMID: 24484606
BRCA1; BRCA2; Prostate cancer; Prostate-specific antigen; Targeted screening
8.  Inhibition of BRCT(BRCA1)-phosphoprotein interaction enhances the cytotoxic effect of Olaparib in breast cancer cells: A proof of concept study for synthetic lethal therapeutic option 
Synthetic lethal therapeutic strategy using poly(adenosine diphosphate [ADP]-ribose) polymerase (PARP) inhibitor Olaparib in carriers of BRCA1 or BRCA2 mutation has shown promise in clinical settings. Since < 5% of patients are BRCA1 or BRCA2 mutation carriers, small molecules that functionally mimic BRCA1 or BRCA2 mutations will extend the synthetic lethal therapeutic option for non-mutation carriers. Here we provide proof of principle for this strategy using a BRCA1 inhibitor peptide 2 that targets the BRCT(BRCA1)-phosphoprotein interaction and mimics the M177R/K BRCA1 mutation. Reciprocal immunoprecipitation and immunoblotting of BRCA1 and Abraxas was used to demonstrate inhibitor 2 targets BRCT(BRCA1)-Abraxas interface. Immunostaining of γH2AX, cell cycle analysis and homologous recombination (HR) assays were conducted to confirm that inhibitor 2 functionally mimics a chemosensitizing BRCA1 mutation. The concept of synthetic lethal therapeutic strategy with the BRCA1 inhibitor 2 and the PARP inhibitor Olaparib was explored in HeLa, MDA-MB-231, and HCC1937 cell lines. The results show that inhibition of BRCA1 by 2 sensitizes HeLa and MDA-MB-231 cells but not HCC1937 to Olaparib mediated growth inhibition and apoptosis. These results provide the basis for developing high affinity BRCT(BRCA1) inhibitors as adjuvants to treat sporadic breast and ovarian cancers.
PMCID: PMC3402595  PMID: 22562176
Synthetic lethal therapeutic strategy; BRCA1 inhibitor; Abraxas; Chemosensitization; Olaparib; IR
9.  The BARD1 Cys557Ser Variant and Breast Cancer Risk in Iceland 
PLoS Medicine  2006;3(7):e217.
Most, if not all, of the cellular functions of the BRCA1 protein are mediated through heterodimeric complexes composed of BRCA1 and a related protein, BARD1. Some breast-cancer-associated BRCA1 missense mutations disrupt the function of the BRCA1/BARD1 complex. It is therefore pertinent to determine whether variants of BARD1 confer susceptibility to breast cancer. Recently, a missense BARD1 variant, Cys557Ser, was reported to be at increased frequencies in breast cancer families. We investigated the role of the BARD1 Cys557Ser variant in a population-based cohort of 1,090 Icelandic patients with invasive breast cancer and 703 controls. We then used a computerized genealogy of the Icelandic population to study the relationships between the Cys557Ser variant and familial clustering of breast cancer.
Methods and Findings
The Cys557Ser allele was present at a frequency of 0.028 in patients with invasive breast cancer and 0.016 in controls (odds ratio [OR] = 1.82, 95% confidence interval [CI] 1.11–3.01, p = 0.014). The alleleic frequency was 0.037 in a high-predisposition group of cases defined by having a family history of breast cancer, early onset of breast cancer, or multiple primary breast cancers (OR = 2.41, 95% CI 1.22–4.75, p = 0.015). Carriers of the common Icelandic BRCA2 999del5 mutation were found to have their risk of breast cancer further increased if they also carried the BARD1 variant: the frequency of the BARD1 variant allele was 0.047 (OR = 3.11, 95% CI 1.16–8.40, p = 0.046) in 999del5 carriers with breast cancer. This suggests that the lifetime probability of a BARD1 Cys557Ser/BRCA2 999del5 double carrier developing breast cancer could approach certainty. Cys557Ser carriers, with or without the BRCA2 mutation, had an increased risk of subsequent primary breast tumors after the first breast cancer diagnosis compared to non-carriers. Lobular and medullary breast carcinomas were overrepresented amongst Cys557Ser carriers. We found that an excess of ancestors of contemporary carriers lived in a single county in the southeast of Iceland and that all carriers shared a SNP haplotype, which is suggestive of a founder event. Cys557Ser was found on the same SNP haplotype background in the HapMap Project CEPH sample of Utah residents.
Our findings suggest that BARD1 Cys557Ser is an ancient variant that confers risk of single and multiple primary breast cancers, and this risk extends to carriers of the BRCA2 999del5 mutation.
Editors' Summary
About 13% of women (one in eight women) will develop breast cancer during their lifetime, but many factors affect the likelihood of any individual woman developing this disease, for example, whether she has had children and at what age, when she started and stopped her periods, and her exposure to certain chemicals or radiation. She may also have inherited a defective gene that affects her risk of developing breast cancer. Some 5%–10% of all breast cancers are familial, or inherited. In 20% of these cases, the gene that is defective is BRCA1 or BRCA2. Inheriting a defective copy of one of these genes greatly increases a woman's risk of developing breast cancer, while researchers think that the other inherited genes that predispose to breast cancer—most of which have not been identified yet—have a much weaker effect. These are described as low-penetrance genes. Inheriting one such gene only slightly increases breast cancer risk; a woman has to inherit several to increase her lifetime risk of cancer significantly.
Why Was This Study Done?
It is important to identify these additional predisposing gene variants because they might provide insights into why breast cancer develops, how to prevent it, and how to treat it. To find low-penetrance genes, researchers do case–control association studies. They find a large group of women with breast cancer (cases) and a similar group of women without cancer (controls), and examine how often a specific gene variant occurs in the two groups. If the variant is found more often in the cases than in the controls, it might be a variant that increases a woman's risk of developing breast cancer.
What Did the Researchers Do and Find?
The researchers involved in this study recruited Icelandic women who had had breast cancer and unaffected women, and looked for a specific variant—the Cys557Ser allele—of a gene called BARD1. They chose BARD1 because the protein it encodes interacts with the protein encoded by BRCA1. Because defects in BRCA1 increase the risk of breast cancer, defects in an interacting protein might have a similar effect. In addition, the Cys557Ser allele has been implicated in breast cancer in other studies. The researchers found that the Cys557Ser allele was nearly twice as common in women with breast cancer as in control women. It was also more common (but not by much) in women who had a family history of breast cancer or who had developed breast cancer more than once. And having the Cys557Ser allele seemed to increase the already high risk of breast cancer in women who had a BRCA2 variant (known as BRCA2 999del5) that accounts for 40% of inherited breast cancer risk in Iceland.
What Do These Findings Mean?
These results indicate that inheriting the BARD1 Cys557Ser allele increases a woman's breast cancer risk but that she is unlikely to have a family history of the disease. Because carrying the Cys557Ser allele only slightly increases a woman's risk of breast cancer, for most women there is no clinical reason to test for this variant. Eventually, when all the low-penetrance genes that contribute to breast cancer risk have been identified, it might be helpful to screen women for the full set to determine whether they are at high risk of developing breast cancer. This will not happen for many years, however, since there might be tens or hundreds of these genes. For women who carry BRCA2 999del5, the situation might be different. It might be worth testing these women for the BARD1 Cys557Ser allele, the researchers explain, because the lifetime probability of developing breast cancer in women carrying both variants might approach 100%. This finding has clinical implications in terms of counseling and monitoring, as does the observation that Cys557Ser carriers have an increased risk of a second, independent breast cancer compared to non-carriers. However, all these findings need to be confirmed in other groups of patients before anyone is routinely tested for the BARD1 Cys557Ser allele.
Additional Information.
Please access these Web sites via the online version of this summary at
• MedlinePlus pages about breast cancer
• Information on breast cancer from the United States National Cancer Institute
• Information on inherited breast cancer from the United States National Human Genome Research Institute
• United States National Cancer Institute information on genetic testing for BRCA1 and BRCA2 variants
• GeneTests pages on the involvement of BRCA1 and BRCA2 in hereditary breast and ovarian cancer
• Cancer Research UK's page on breast cancer statistics
In a population-based cohort of 1090 Icelandic patients, a Cys557Ser missense variant of the BARD1 gene, which interacts with BRCA1, increased the risk of single and multiple primary breast cancers.
PMCID: PMC1479388  PMID: 16768547
10.  Extracellular Matrix Enhances Heregulin-Dependent BRCA1 Phosphorylation and Suppresses BRCA1 Expression through Its C Terminus 
Molecular and Cellular Biology  2003;23(2):579-593.
Germ line mutations in the breast cancer susceptibility gene BRCA1 account for the increased risk of early onset of familial breast cancer, whereas overexpression of the ErbB family of receptor tyrosine kinases has been linked to the development of nonfamilial or sporadic breast cancer. To analyze whether there is a link between these two regulatory molecules, we studied the effects of ErbB-2 activation by heregulin (HRG) on BRCA1 function. It was previously demonstrated that HRG induced the phosphorylation of BRCA1, which was mediated by the phosphatidylinositol 3-kinase (PI3K)/Akt pathway. Since altered interaction between cells and the surrounding extracellular matrix (ECM) is a common feature in a variety of tumors and since ECM modulates intracellular signaling, we hypothesized that ECM may affect the expression and HRG-dependent phosphorylation of BRCA1. Following stimulation by HRG, a strong increase in [3H]thymidine incorporation was observed in human T47D breast cancer cells seeded on plastic (PL). When T47D cells were seeded on laminin (LAM) or Matrigel, HRG induced a significantly higher proliferation than it did in cells seeded on PL. T47D cells seeded on poly-l-lysine had an abrogated mitogenic response, indicating the involvement of integrins in this process. HRG treatment induced a transient phosphorylation of BRCA1 that was enhanced in T47D cells grown on LAM. LAM-enhanced BRCA1 phosphorylation was mediated through α6 integrin upon HRG stimulation. Accordingly, T47D cells grown on LAM had the greatest increase in ErbB-2 activation, PI3K activity, and phosphorylation of Akt. A similar pattern of BRCA1 mRNA expression was observed when T47D cells were seeded on PL, LAM, or COL4. There was a significant decrease in the steady state of the BRCA1 mRNA level on both the LAM and COL4 matrices compared to that for cells seeded on PL. In addition, HRG stimulation caused a significant decrease in BRCA1 mRNA expression that was dependent on protein synthesis. Pretreatment with both the calpain inhibitor ALLN (N-acetyl-Leu-Leu-norleucinal) and the proteosome inhibitor lactacystin inhibited the HRG-induced down-regulation of BRCA1 mRNA expression. Likewise, there was a strong decrease in the protein level of BRCA1 in T47D cells 4 h after treatment with HRG compared to its level in control nontreated T47D cells. Pretreatment with the proteosome inhibitors ALLN, lactacystin, and PSI [N-benzyloxycarbonyl-Ile-Glu-(O-t-butyl)-Ala-leucinal] inhibited also the HRG-induced down-regulation of BRCA1 protein in breast cancer cells. Interestingly, BRCA1 mRNA expression in HCC-1937 breast cancer cells, which express C-terminally truncated BRCA1, was not affected by either LAM or CL4. No phosphorylation of BRCA1 from HCC-1937 cells was observed in response to HRG. While Cdk4 phosphorylated wild-type BRCA1 in response to HRG in T47D cells, Cdk4 failed to phosphorylate the truncated form of BRCA1 in HCC-1937 cells. Furthermore, overexpression of wild-type BRCA1 in HCC-1937 cells resulted in the phosphorylation of BRCA1 and decreased BRCA1 expression upon HRG stimulation while overexpression of truncated BRCA1 in T47D cells resulted in a lack of BRCA1 phosphorylation and restoration of BRCA1 expression. These findings suggest that ECM enhances HRG-dependent BRCA1 phosphorylation and that ECM and HRG down-regulate BRCA1 expression in breast cancer cells. Furthermore, ECM suppresses BRCA1 expression through the C terminus of BRCA1.
PMCID: PMC151527  PMID: 12509456
11.  Quantitative copy number analysis by Multiplex Ligation-dependent Probe Amplification (MLPA) of BRCA1-associated breast cancer regions identifies BRCAness 
Breast Cancer Research : BCR  2011;13(5):R107.
Our group has previously employed array Comparative Genomic Hybridization (aCGH) to assess the genomic patterns of BRCA1-mutated breast cancers. We have shown that the so-called BRCA1-likeaCGH profile is also present in about half of all triple-negative sporadic breast cancers and is predictive for benefit from intensified alkylating chemotherapy. As aCGH is a rather complex method, we translated the BRCA1aCGH profile to a Multiplex Ligation-dependent Probe Amplification (MLPA) assay, to identify both BRCA1-mutated breast cancers and sporadic cases with a BRCA1-likeaCGH profile.
The most important genomic regions of the original aCGH based classifier (3q22-27, 5q12-14, 6p23-22, 12p13, 12q21-23, 13q31-34) were mapped to a set of 34 MLPA probes. The training set consisted of 39 BRCA1-likeaCGH breast cancers and 45 non-BRCA1-likeaCGH breast cancers, which had previously been analyzed by aCGH. The BRCA1-likeaCGH group consisted of germline BRCA1-mutated cases and sporadic tumours with low BRCA1 gene expression and/or BRCA1 promoter methylation. We trained a shrunken centroids classifier on the training set and validation was performed on an independent test set of 40 BRCA1-likeaCGH breast cancers and 32 non-BRCA1-likeaCGH breast cancer tumours. In addition, we validated the set prospectively on 69 new triple-negative tumours.
BRCAness in the training set of 84 tumours could accurately be predicted by prediction analysis of microarrays (PAM) (accuracy 94%). Application of this classifier on the independent validation set correctly predicted BRCA-like status of 62 out of 72 breast tumours (86%). Sensitivity and specificity were 85% and 87%, respectively. When the MLPA-test was subsequently applied to 46 breast tumour samples from a randomized clinical trial, the same survival benefit for BRCA1-like tumours associated with intensified alkylating chemotherapy was shown as was previously reported using the aCGH assay.
Since the MLPA assay can identify BRCA1-deficient breast cancer patients, this method could be applied both for clinical genetic testing and as a predictor of treatment benefit. BRCA1-like tumours are highly sensitive to chemotherapy with DNA damaging agents, and most likely to poly ADP ribose polymerase (PARP)-inhibitors. The MLPA assay is rapid and robust, can easily be multiplexed, and works well with DNA derived from paraffin-embedded tissues.
PMCID: PMC3262220  PMID: 22032731
12.  BRCAness: Finding the Achilles Heel in Ovarian Cancer 
The Oncologist  2012;17(7):956-962.
This article presents a comprehensive review of the literature on the role of BRCAness in ovarian cancer with respect to BRCA function, methods of BRCA epigenetic defect detection and molecular profiling, and the implications of BRCA dysfunction for ovarian cancer treatment.
Ovarian cancer is the leading cause of death among gynecological cancers. It exhibits great heterogeneity in tumor biology and treatment response. Germline mutations of DNA repair genes BRCA1/2 are the fundamental defects in hereditary ovarian cancer that expresses a distinct phenotype of high response rates to platinum agents, improved disease-free intervals and survival rates, and high-grade serous histology. The term “BRCAness” describes the phenotypic traits that some sporadic ovarian tumors share with tumors in BRCA1/2 germline mutation carriers and reflects similar causative molecular abnormalities. BRCA pathway studies and molecular profiling reveal BRCA-related defects in almost half of the cases of ovarian cancer. BRCA-like tumors are particularly sensitive to DNA-damaging agents (e.g., platinum agents) because of inadequate BRCA-mediated DNA repair mechanisms, such as nucleotide-excision repair and homologous recombination (HR). Additional inhibition of other DNA repair pathways leads to synthetic lethality in HR-deficient cells; this has been employed in the treatment of BRCA-like ovarian tumors with poly(ADP-ribose) polymerase inhibitors with promising results. This article presents a comprehensive review of the relevant literature on the role of BRCAness in ovarian cancer with respect to BRCA function, methods of BRCA epigenetic defect detection and molecular profiling, and the implications of BRCA dysfunction in the treatment of ovarian cancer.
PMCID: PMC3399652  PMID: 22673632
BRCAness; BRCA1/2; Ovarian cancer; PARP inhibitors; Synthetic lethality
13.  CpG island hypermethylation of BRCA1 and loss of pRb as co-occurring events in basal/triple-negative breast cancer 
Epigenetics  2011;6(5):638-649.
Triple-negative breast cancer (TNBC) occurs in approximately 15% of all breast cancer patients, and the incidence of TNBC is greatly increased in BRCA1 mutation carriers. This study aimed to assess the impact of BRCA1 promoter methylation with respect to breast cancer subtypes in sporadic disease. Tissue microarrays (TMAs) were constructed representing tumors from 303 patients previously screened for BRCA1 germline mutations, of which a subset of 111 sporadic tumors had previously been analyzed with respect to BRCA1 methylation. Additionally, a set of eight tumors from BRCA1 mutation carriers were included on the TMAs. Expression analysis was performed on TMAs by immunohistochemistry (IHC) for BRCA1, pRb, p16, p53, PTEN, ER, PR, HER2, CK5/6, CK8, CK18, EGFR, MUC1, and Ki-67. Data on BRCA1 aberrations and IHC expression was examined with respect to breast cancer-specific survival. The results demonstrate that CpG island hypermethylation of BRCA1 significantly associates with the basal/triple-negative subtype. Low expression of pRb, and high/intense p16, were associated with BRCA1 promoter hypermethylation, and the same effects were seen in BRCA1 mutated tumors. The expression patterns of BRCA1, pRb, p16 and PTEN were highly correlated, and define a subgroup of TNBCs characterized by BRCA1 aberrations, high Ki-67 (≥ 40%) and favorable disease outcome. In conclusion, our findings demonstrate that epigenetic inactivation of the BRCA1 gene associates with RB/p16 dysfunction in promoting TNBCs. The clinical implications relate to the potential use of targeted treatment based on PARP inhibitors in sporadic TNBCs, wherein CpG island hypermethylation of BRCA1 represents a potential marker of therapeutic response.
PMCID: PMC3121973  PMID: 21593597
BRCA1; methylation; epigenetics; triple negative; breast cancer; retionblastoma tumor suppressor gene; pRb; p16
14.  Basal cytokeratins in breast tumours among BRCA1, BRCA2 and mutation-negative breast cancer families 
Finding new immunohistochemical markers that are specific to hereditary breast cancer could help us to select candidates for BRCA1/BRCA2 mutation testing and to understand the biological pathways of tumour development.
Using breast cancer tumour microarrays, immunohistochemical expression of cytokeratin (CK)-5/6, CK-14 and CK-17 was evaluated in breast tumours from BRCA1 families (n = 46), BRCA2 families (n = 40), non-BRCA1/BRCA2 families (n = 358) and familial breast cancer patients with one first-degree relative affected by breast or ovarian cancer (n = 270), as well as from patients with sporadic breast cancer (n = 364). Staining for CK-5/6, CK-14 and CK-17 was compared between these groups and correlated with other clinical and histological factors.
CK-5/6, CK-14 and CK-17 were detected mostly among oestrogen receptor (ER)-negative, progesterone receptor (PR)-negative and high-grade tumours. We found the highest percentages of samples positive for these CKs among ER-negative/HER2-negative tumours. In univariate analysis, CK-14 was significantly associated with tumours from BRCA1 (39%; P < 0.0005), BRCA2 (27%; P = 0.011), and non-BRCA1/BRCA2 (21%; P < 0.005) families, as compared with sporadic tumours (10%). However, in multivariate analysis, CKs were not found to be independently associated with BRCA1 or BRCA2 mutation status, and the most effective predictors of BRCA1 mutations were age at onset, HER2 status, and either ER or PR status.
Although our study confirms that basal CKs can help to identify BRCA1 mutation carriers, this effect was weaker than previously suggested and CKs did not independently predict BRCA1 mutation either from sporadic or familial breast cancer cases. The most effective, independent predictors of BRCA1 mutations were age at onset, HER2 status, and either ER or PR status, as compared with sporadic or non-BRCA1/BRCA2 cancers.
PMCID: PMC2374973  PMID: 18275599
15.  High frequency of BRCA1, but not CHEK2 or NBS1 (NBN), founder mutations in Russian ovarian cancer patients 
A significant portion of ovarian cancer (OC) cases is caused by germ-line mutations in BRCA1 or BRCA2 genes. BRCA testing is cheap in populations with founder effect and therefore recommended for all patients with OC diagnosis. Recurrent mutations constitute the vast majority of BRCA defects in Russia, however their impact in OC morbidity has not been yet systematically studied. Furthermore, Russian population is characterized by a relatively high frequency of CHEK2 and NBS1 (NBN) heterozygotes, but it remains unclear whether these two genes contribute to the OC risk.
The study included 354 OC patients from 2 distinct, geographically remote regions (290 from North-Western Russia (St.-Petersburg) and 64 from the south of the country (Krasnodar)). DNA samples were tested by allele-specific PCR for the presence of 8 founder mutations (BRCA1 5382insC, BRCA1 4153delA, BRCA1 185delAG, BRCA1 300T>G, BRCA2 6174delT, CHEK2 1100delC, CHEK2 IVS2+1G>A, NBS1 657del5). In addition, literature data on the occurrence of BRCA1, BRCA2, CHEK2 and NBS1 mutations in non-selected ovarian cancer patients were reviewed.
BRCA1 5382insC allele was detected in 28/290 (9.7%) OC cases from the North-West and 11/64 (17.2%) OC patients from the South of Russia. In addition, 4 BRCA1 185delAG, 2 BRCA1 4153delA, 1 BRCA2 6174delT, 2 CHEK2 1100delC and 1 NBS1 657del5 mutation were detected. 1 patient from Krasnodar was heterozygous for both BRCA1 5382insC and NBS1 657del5 variants.
Founder BRCA1 mutations, especially BRCA1 5382insC variant, are responsible for substantial share of OC morbidity in Russia, therefore DNA testing has to be considered for every OC patient of Russian origin. Taken together with literature data, this study does not support the contribution of CHEK2 in OC risk, while the role of NBS1 heterozygosity may require further clarification.
PMCID: PMC2664323  PMID: 19338682
16.  BRCA Mutation Frequency and Patterns of Treatment Response in BRCA Mutation–Positive Women With Ovarian Cancer: A Report From the Australian Ovarian Cancer Study Group 
Journal of Clinical Oncology  2012;30(21):2654-2663.
The frequency of BRCA1 and BRCA2 germ-line mutations in women with ovarian cancer is unclear; reports vary from 3% to 27%. The impact of germ-line mutation on response requires further investigation to understand its impact on treatment planning and clinical trial design.
Patients and Methods
Women with nonmucinous ovarian carcinoma (n = 1,001) enrolled onto a population-based, case-control study were screened for point mutations and large deletions in both genes. Survival outcomes and responses to multiple lines of chemotherapy were assessed.
Germ-line mutations were found in 14.1% of patients overall, including 16.6% of serous cancer patients (high-grade serous, 22.6%); 44% had no reported family history of breast or ovarian cancer. Patients carrying germ-line mutations had improved rates of progression-free and overall survival. In the relapse setting, patients carrying mutations more frequently responded to both platin- and nonplatin-based regimens than mutation-negative patients, even in patients with early relapse after primary treatment. Mutation-negative patients who responded to multiple cycles of platin-based treatment were more likely to carry somatic BRCA1/2 mutations.
BRCA mutation status has a major influence on survival in ovarian cancer patients and should be an additional stratification factor in clinical trials. Treatment outcomes in BRCA1/2 carriers challenge conventional definitions of platin resistance, and mutation status may be able to contribute to decision making and systemic therapy selection in the relapse setting. Our data, together with the advent of poly(ADP-ribose) polymerase inhibitor trials, supports the recommendation that germ-line BRCA1/2 testing should be offered to all women diagnosed with nonmucinous, ovarian carcinoma, regardless of family history.
PMCID: PMC3413277  PMID: 22711857
17.  AURKA F31I Polymorphism and Breast Cancer Risk in BRCA1 and BRCA2 Mutation Carriers: A CIMBA study 
Couch, Fergus J. | Sinilnikova, Olga | Vierkant, Robert A | Pankratz, V. Shane | Fredericksen, Zachary S. | Stoppa-Lyonnet, Dominique | Coupier, Isabelle | Hughes, David | Hardouin, Agnès | Berthet, Pascaline | Peock, Susan | Cook, Margaret | Baynes, Caroline | Hodgson, Shirley | Morrison, Patrick J. | Porteous, Mary E. | Jakubowska, Anna | Lubinski, Jan | Gronwald, Jacek | Spurdle, Amanda B. | Schmutzler, Rita | Versmold, Beatrix | Engel, Christoph | Meindl, Alfons | Sutter, Christian | Horst, Jurgen | Schaefer, Dieter | Offit, Kenneth | Kirchhoff, Tomas | Andrulis, Irene L. | Ilyushik, Eduard | Glendon, Gordon | Devilee, Peter | Vreeswijk, Maaike P.G. | Vasen, Hans F.A. | Borg, Ake | Backenhorn, Katja | Struewing, Jeffery P. | Greene, Mark H. | Neuhausen, Susan L. | Rebbeck, Timothy R. | Nathanson, Katherine | Domchek, Susan | Wagner, Theresa | Garber, Judy E. | Szabo, Csilla | Zikan, Michal | Foretova, Lenka | Olson, Janet E. | Sellers, Thomas A. | Lindor, Noralane | Nevanlinna, Heli | Tommiska, Johanna | Aittomaki, Kristiina | Hamann, Ute | Rashid, Muhammad U. | Torres, Diana | Simard, Jacques | Durocher, Francine | Guenard, Frederic | Lynch, Henry T. | Isaacs, Claudine | Weitzel, Jeffrey | Olopade, Olufunmilayo I. | Narod, Steven | Daly, Mary B. | Godwin, Andrew K. | Tomlinson, Gail | Easton, Douglas F. | Chenevix-Trench, Georgia | Antoniouon, Antonis C.
The AURKA oncogene is associated with abnormal chromosome segregation and aneuploidy and predisposition to cancer. Amplification of AURKA has been detected at higher frequency in tumors from BRCA1 and BRCA2 mutation carriers than in sporadic breast tumors, suggesting that overexpression of AURKA and inactivation of BRCA1 and BRCA2 co-operate during tumor development and progression. The F31I polymorphism in AURKA has been associated with breast cancer risk in the homozygous state in prior studies. We evaluated whether the AURKA F31I polymorphism modifies breast cancer risk in BRCA1 and BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). CIMBA was established to provide sufficient statistical power through increased numbers of mutation carriers to identify polymorphisms that act as modifiers of cancer risk and can refine breast cancer risk estimates in BRCA1 and BRCA2 mutation carriers. A total of 4935 BRCA1 and 2241 BRCA2 mutation carriers and 11 individuals carrying both BRCA1 and BRCA2 mutations were genotyped for F31I. Overall, homozygosity for the 31I allele was not significantly associated with breast cancer risk in BRCA1 and BRCA2 carriers combined (HR = 0.91; 95% CI 0.77-1.06). Similarly, no significant association was seen in BRCA1 (HR = 0.90; 95% CI 0.75-1.08) or BRCA2 carriers (HR = 0.93; 95% CI 0.67-1.29) or when assessing the modifying effects of either bilateral prophylactic oophorectomy or menopausal status of BRCA1 and BRCA2 carriers. In summary, the F31I polymorphism in AURKA is not associated with a modified risk of breast cancer in BRCA1 and BRCA2 carriers.
PMCID: PMC2775799  PMID: 17627006
BRCA1; BRCA2; AURKA; CIMBA; Breast cancer risk
18.  DNA Glycosylases Involved in Base Excision Repair May Be Associated with Cancer Risk in BRCA1 and BRCA2 Mutation Carriers 
Osorio, Ana | Milne, Roger L. | Kuchenbaecker, Karoline | Vaclová, Tereza | Pita, Guillermo | Alonso, Rosario | Peterlongo, Paolo | Blanco, Ignacio | de la Hoya, Miguel | Duran, Mercedes | Díez, Orland | Ramón y Cajal, Teresa | Konstantopoulou, Irene | Martínez-Bouzas, Cristina | Andrés Conejero, Raquel | Soucy, Penny | McGuffog, Lesley | Barrowdale, Daniel | Lee, Andrew | SWE-BRCA,  | Arver, Brita | Rantala, Johanna | Loman, Niklas | Ehrencrona, Hans | Olopade, Olufunmilayo I. | Beattie, Mary S. | Domchek, Susan M. | Nathanson, Katherine | Rebbeck, Timothy R. | Arun, Banu K. | Karlan, Beth Y. | Walsh, Christine | Lester, Jenny | John, Esther M. | Whittemore, Alice S. | Daly, Mary B. | Southey, Melissa | Hopper, John | Terry, Mary B. | Buys, Saundra S. | Janavicius, Ramunas | Dorfling, Cecilia M. | van Rensburg, Elizabeth J. | Steele, Linda | Neuhausen, Susan L. | Ding, Yuan Chun | Hansen, Thomas v. O. | Jønson, Lars | Ejlertsen, Bent | Gerdes, Anne-Marie | Infante, Mar | Herráez, Belén | Moreno, Leticia Thais | Weitzel, Jeffrey N. | Herzog, Josef | Weeman, Kisa | Manoukian, Siranoush | Peissel, Bernard | Zaffaroni, Daniela | Scuvera, Giulietta | Bonanni, Bernardo | Mariette, Frederique | Volorio, Sara | Viel, Alessandra | Varesco, Liliana | Papi, Laura | Ottini, Laura | Tibiletti, Maria Grazia | Radice, Paolo | Yannoukakos, Drakoulis | Garber, Judy | Ellis, Steve | Frost, Debra | Platte, Radka | Fineberg, Elena | Evans, Gareth | Lalloo, Fiona | Izatt, Louise | Eeles, Ros | Adlard, Julian | Davidson, Rosemarie | Cole, Trevor | Eccles, Diana | Cook, Jackie | Hodgson, Shirley | Brewer, Carole | Tischkowitz, Marc | Douglas, Fiona | Porteous, Mary | Side, Lucy | Walker, Lisa | Morrison, Patrick | Donaldson, Alan | Kennedy, John | Foo, Claire | Godwin, Andrew K. | Schmutzler, Rita Katharina | Wappenschmidt, Barbara | Rhiem, Kerstin | Engel, Christoph | Meindl, Alfons | Ditsch, Nina | Arnold, Norbert | Plendl, Hans Jörg | Niederacher, Dieter | Sutter, Christian | Wang-Gohrke, Shan | Steinemann, Doris | Preisler-Adams, Sabine | Kast, Karin | Varon-Mateeva, Raymonda | Gehrig, Andrea | Stoppa-Lyonnet, Dominique | Sinilnikova, Olga M. | Mazoyer, Sylvie | Damiola, Francesca | Poppe, Bruce | Claes, Kathleen | Piedmonte, Marion | Tucker, Kathy | Backes, Floor | Rodríguez, Gustavo | Brewster, Wendy | Wakeley, Katie | Rutherford, Thomas | Caldés, Trinidad | Nevanlinna, Heli | Aittomäki, Kristiina | Rookus, Matti A. | van Os, Theo A. M. | van der Kolk, Lizet | de Lange, J. L. | Meijers-Heijboer, Hanne E. J. | van der Hout, A. H. | van Asperen, Christi J. | Gómez Garcia, Encarna B. | Hoogerbrugge, Nicoline | Collée, J. Margriet | van Deurzen, Carolien H. M. | van der Luijt, Rob B. | Devilee, Peter | HEBON,  | Olah, Edith | Lázaro, Conxi | Teulé, Alex | Menéndez, Mireia | Jakubowska, Anna | Cybulski, Cezary | Gronwald, Jacek | Lubinski, Jan | Durda, Katarzyna | Jaworska-Bieniek, Katarzyna | Johannsson, Oskar Th. | Maugard, Christine | Montagna, Marco | Tognazzo, Silvia | Teixeira, Manuel R. | Healey, Sue | Investigators, kConFab | Olswold, Curtis | Guidugli, Lucia | Lindor, Noralane | Slager, Susan | Szabo, Csilla I. | Vijai, Joseph | Robson, Mark | Kauff, Noah | Zhang, Liying | Rau-Murthy, Rohini | Fink-Retter, Anneliese | Singer, Christian F. | Rappaport, Christine | Geschwantler Kaulich, Daphne | Pfeiler, Georg | Tea, Muy-Kheng | Berger, Andreas | Phelan, Catherine M. | Greene, Mark H. | Mai, Phuong L. | Lejbkowicz, Flavio | Andrulis, Irene | Mulligan, Anna Marie | Glendon, Gord | Toland, Amanda Ewart | Bojesen, Anders | Pedersen, Inge Sokilde | Sunde, Lone | Thomassen, Mads | Kruse, Torben A. | Jensen, Uffe Birk | Friedman, Eitan | Laitman, Yael | Shimon, Shani Paluch | Simard, Jacques | Easton, Douglas F. | Offit, Kenneth | Couch, Fergus J. | Chenevix-Trench, Georgia | Antoniou, Antonis C. | Benitez, Javier
PLoS Genetics  2014;10(4):e1004256.
Single Nucleotide Polymorphisms (SNPs) in genes involved in the DNA Base Excision Repair (BER) pathway could be associated with cancer risk in carriers of mutations in the high-penetrance susceptibility genes BRCA1 and BRCA2, given the relation of synthetic lethality that exists between one of the components of the BER pathway, PARP1 (poly ADP ribose polymerase), and both BRCA1 and BRCA2. In the present study, we have performed a comprehensive analysis of 18 genes involved in BER using a tagging SNP approach in a large series of BRCA1 and BRCA2 mutation carriers. 144 SNPs were analyzed in a two stage study involving 23,463 carriers from the CIMBA consortium (the Consortium of Investigators of Modifiers of BRCA1 and BRCA2). Eleven SNPs showed evidence of association with breast and/or ovarian cancer at p<0.05 in the combined analysis. Four of the five genes for which strongest evidence of association was observed were DNA glycosylases. The strongest evidence was for rs1466785 in the NEIL2 (endonuclease VIII-like 2) gene (HR: 1.09, 95% CI (1.03–1.16), p = 2.7×10−3) for association with breast cancer risk in BRCA2 mutation carriers, and rs2304277 in the OGG1 (8-guanine DNA glycosylase) gene, with ovarian cancer risk in BRCA1 mutation carriers (HR: 1.12 95%CI: 1.03–1.21, p = 4.8×10−3). DNA glycosylases involved in the first steps of the BER pathway may be associated with cancer risk in BRCA1/2 mutation carriers and should be more comprehensively studied.
Author Summary
Women harboring a germ-line mutation in the BRCA1 or BRCA2 genes have a high lifetime risk to develop breast and/or ovarian cancer. However, not all carriers develop cancer and high variability exists regarding age of onset of the disease and type of tumor. One of the causes of this variability lies in other genetic factors that modulate the phenotype, the so-called modifier genes. Identification of these genes might have important implications for risk assessment and decision making regarding prevention of the disease. Given that BRCA1 and BRCA2 participate in the repair of DNA double strand breaks, here we have investigated whether variations, Single Nucleotide Polymorphisms (SNPs), in genes participating in other DNA repair pathway may be associated with cancer risk in BRCA carriers. We have selected the Base Excision Repair pathway because BRCA defective cells are extremely sensitive to the inhibition of one of its components, PARP1. Thanks to a large international collaborative effort, we have been able to identify at least two SNPs that are associated with increased cancer risk in BRCA1 and BRCA2 mutation carriers respectively. These findings could have implications not only for risk assessment, but also for treatment of BRCA1/2 mutation carriers with PARP inhibitors.
PMCID: PMC3974638  PMID: 24698998
19.  Enhancement of synthetic lethality via combinations of ABT-888 (a PARP inhibitor) and carboplatin in vitro and in vivo using BRCA1 and BRCA2 isogenic models 
Molecular cancer therapeutics  2012;11(9):1948-1958.
Individuals with an inherited BRCA1 or BRCA2 mutation have an elevated risk of developing breast cancer (BC). The resulting tumors typically lack homologous recombination repair, as do a subset of sporadic tumors with acquired BRCA deficiency. Clinical responses to monotherapy with platinum drugs or poly(ADP)ribose polymerase (PARP) inhibitors (PARPi) have been demonstrated for BRCA-associated cancers. However, there is limited data on combination therapy with PARPi and platinum drugs, the mechanism of action of this combination and the role of BRCA1 or BRCA2 in chemosensitivity. We compared the efficacy of ABT-888 (a PARPi) with that of cisplatin or carboplatin (platinum drugs) alone or in combinations by examining survival of treated Brca-proficient and -deficient mouse embryonic stem cells (mESC). In addition, drug-induced growth inhibition of a BRCA1 and a BRCA2 null cell line were compared to their isogenic BRCA-complemented lines. Whereas each monotherapy killed or inhibited proliferation of Brca/BRCA-deficient cells, an enhanced effect was observed after treatment with ABT-888 in combination with carboplatin. Moreover, the ABT-888/carboplatin combination delayed tumor growth in Brca2 xenografts. The drugs caused DNA damage, apoptosis and greater PARP activity in Brca/BRCA-deficient cells, and these effects correlated with increased chemosensitivity. Our data suggest that ABT-888 and carboplatin combination treatment will be more successful than monotherapy in addressing many BRCA-associated cancers. A randomized phase II trial has recently been initiated to test this hypothesis to assist in the discovery of more effective therapies for BRCA patients.
PMCID: PMC3551628  PMID: 22778154
BRCA1; BRCA2; Chemotherapy; PARP inhibitor; Platinum Drugs
20.  BRCA Mutation Testing in Determining Breast Cancer Therapy 
Cancer journal (Sudbury, Mass.)  2011;17(6):492-499.
BRCA-mutation associated breast cancer differs from sporadic breast cancer with regard to future cancer risks and sensitivity to systemic therapies. Now that rapid genetic testing for BRCA1 and BRCA2 mutations is available at the time of breast cancer diagnosis, BRCA mutation status can be considered when making treatment and prevention decisions for BRCA mutation carriers with breast cancer. This article reviews surgical options for management of affected BRCA mutation carriers with emphasis on the risks of ipsilateral recurrence and contralateral breast cancer. The roles of breast conserving surgery, prophylactic mastectomy and oophorectomy are reviewed. In addition, sensitivity of BRCA mutation-associated breast cancer to endocrine therapy, platinum chemotherapy and poly (ADP-Ribose) polymerase inhibitors is reviewed.
PMCID: PMC3240813  PMID: 22157293
BRCA1; BRCA2; Breast cancer; Treatment
21.  Epigenetic silencing and deletion of the BRCA1 gene in sporadic breast cancer 
Breast Cancer Research  2006;8(4):R38.
BRCA1 or BRCA2 germline mutations increase the risk of developing breast cancer. Tumour cells from germline mutation carriers have frequently lost the wild-type allele. This is predicted to result in genomic instability where cell survival depends upon dysfunctional checkpoint mechanisms. Tumorigenic potential could then be acquired through further genomic alterations. Surprisingly, somatic BRCA mutations are not found in sporadic breast tumours. BRCA1 methylation has been shown to occur in sporadic breast tumours and to be associated with reduced gene expression. We examined the frequency of BRCA1 methylation in 143 primary sporadic breast tumours along with BRCA1 copy number alterations and tumour phenotype.
Primary sporadic breast tumours were analysed for BRCA1α promoter methylation by methylation specific PCR and for allelic imbalance (AI) at BRCA1 and BRCA2 loci by microsatellite analysis and TP53 (also known as p53) mutations by constant denaturing gel electrophoresis. The BRCA1 methylated tumours were analysed for BRCA1 copy alterations by fluorescence in situ hybridisation and BRCA1 expression by immunostaining.
BRCA1 methylation was found in 13/143 (9.1%) sporadic breast tumours. The BRCA1 methylated tumours were significantly associated with estrogen receptor (ER) negativity (P = 0.0475) and displayed a trend for BRCA1 AI (P = 0.0731) as well as young-age at diagnosis (≤ 55; P = 0.0898). BRCA1 methylation was not associated with BRCA2 AI (P = 0.5420), although a significant association was found between BRCA1 AI and BRCA2 AI (P < 0.0001).
Absent/markedly reduced BRCA1 expression was observed in 9/13 BRCA1 methylated tumours, most of which had BRCA1 deletion. An elevated TP53 mutation frequency was found among BRCA1 methylated tumours (38.5%) compared with non-methylated tumours (17.2%). The BRCA1 methylated tumours were mainly of tumour grade 3 (7/13) and infiltrating ductal type (12/13). Only one methylated tumour was of grade 1.
BRCA1 methylation is frequent in primary sporadic breast tumours. We found an indication for BRCA1 methylation to be associated with AI at the BRCA1 locus. Almost all BRCA1 methylated tumours with absent/markedly reduced BRCA1 expression (8/9) displayed BRCA1 deletion. Thus, epigenetic silencing and deletion of the BRCA1 gene might serve as Knudson's two 'hits' in sporadic breast tumorigenesis. We observed phenotypic similarities between BRCA1 methylated and familial BRCA1 tumours, based on BRCA1 deletion, TP53 mutations, ER status, young age at diagnosis and tumour grade.
PMCID: PMC1779478  PMID: 16846527
22.  Towards Evidence-Based Management of Inherited Breast and Breast-Ovarian Cancer 
Inherited breast-ovarian cancer was described in 1866. The underlying genetic defects in BRCA1/2 were demonstrated 128 years later. We now have 10 years of experience with genetic testing in BRCA kindreds. The majority of breast cancer kindreds (familial breast cancer) do not demonstrate ovarian cancer and are not associated with BRCA mutations. The effect of early diagnosis and treatment is monitored through international collaborations.
BRCA1-associated breast cancer is biologically different from other breast cancers, including a worse prognosis. BRCA2-associated breast cancer is, beside early onset, in many ways similar to sporadic breast cancer. Mammography screening of the high risk groups aiming at early diagnosis and treatment, seems promising for familial breast cancer and for BRCA2-associated breast cancer, but numbers included for BRCA2 carriers are limited. BRCA1-carriers have worse prognosis, and the potential benefit of MRI for early diagnosis is now being explored. Early diagnosis and treatment of ovarian cancer does not substantially improve survival, and prophylactic oophorectomy at the end of childbearing ages is advocated. Prophylactic mastectomy is debated, and we may await the results of MRI trials before recommending this option. Familial breast cancer and BRCA2-associated breast cancers are often oestrogen receptor positive, and may be prevented by oestrogen blockers/inhibitors. Oophorectomy prevents ovarian cancer, and may possibly prevent both receptor positive and receptor negative breast cancer as well, also while using HRT. Oral contraceptives may reduce ovarian cancer risk and increase breast cancer risk, irrespective of initial risk and genetic subgroup.
PMCID: PMC2839988  PMID: 20233478
inherited; breast cancer; ovarian cancer; BRCA; prevention
23.  Population-Based Study of the Risk of Second Primary Contralateral Breast Cancer Associated With Carrying a Mutation in BRCA1 or BRCA2 
Journal of Clinical Oncology  2010;28(14):2404-2410.
Women with breast cancer diagnosed early in life comprise a substantial portion of those tested for BRCA1/BRCA2 mutations; however, little information is available on the subsequent risks of contralateral breast cancer in mutation carriers. This study assessed the risk of subsequent contralateral breast cancer associated with carrying a BRCA1 or BRCA2 mutation.
Patients and Methods
In this nested case-control study, patients with contralateral breast cancer diagnosed 1 year or more after a first primary breast cancer (n = 705) and controls with unilateral breast cancer (n = 1,398) were ascertained from an underlying population-based cohort of 52,536 women diagnosed with a first invasive breast cancer before age 55 years. Interviews and medical record reviews were used to collect risk factor and treatment histories. All women were tested for BRCA1/BRCA2 mutations. Relative (rate ratios) and absolute (5- and 10-year cumulative) risks of developing contralateral breast cancer following a first invasive breast cancer were computed.
Compared with noncarriers, BRCA1 and BRCA2 mutation carriers had 4.5-fold (95% CI, 2.8- to 7.1-fold) and 3.4-fold (95% CI, 2.0- to 5.8-fold) increased risks of contralateral breast cancer, respectively. The relative risk of contralateral breast cancer for BRCA1 mutation carriers increased as age of first diagnosis decreased. Age-specific cumulative risks are provided for clinical guidance.
The risks of subsequent contralateral breast cancer are substantial for women who carry a BRCA1/BRCA2 mutation. These findings have important clinical relevance regarding the assessment of BRCA1/BRCA2 status in patients with breast cancer and the counseling and clinical management of patients found to carry a mutation.
PMCID: PMC2881721  PMID: 20368571
24.  BRCA1 and BRCA2 Missense Variants of High and Low Clinical Significance Influence Lymphoblastoid Cell Line Post-Irradiation Gene Expression 
PLoS Genetics  2008;4(5):e1000080.
The functional consequences of missense variants in disease genes are difficult to predict. We assessed if gene expression profiles could distinguish between BRCA1 or BRCA2 pathogenic truncating and missense mutation carriers and familial breast cancer cases whose disease was not attributable to BRCA1 or BRCA2 mutations (BRCAX cases). 72 cell lines from affected women in high-risk breast ovarian families were assayed after exposure to ionising irradiation, including 23 BRCA1 carriers, 22 BRCA2 carriers, and 27 BRCAX individuals. A subset of 10 BRCAX individuals carried rare BRCA1/2 sequence variants considered to be of low clinical significance (LCS). BRCA1 and BRCA2 mutation carriers had similar expression profiles, with some subclustering of missense mutation carriers. The majority of BRCAX individuals formed a distinct cluster, but BRCAX individuals with LCS variants had expression profiles similar to BRCA1/2 mutation carriers. Gaussian Process Classifier predicted BRCA1, BRCA2 and BRCAX status, with a maximum of 62% accuracy, and prediction accuracy decreased with inclusion of BRCAX samples carrying an LCS variant, and inclusion of pathogenic missense carriers. Similarly, prediction of mutation status with gene lists derived using Support Vector Machines was good for BRCAX samples without an LCS variant (82–94%), poor for BRCAX with an LCS (40–50%), and improved for pathogenic BRCA1/2 mutation carriers when the gene list used for prediction was appropriate to mutation effect being tested (71–100%). This study indicates that mutation effect, and presence of rare variants possibly associated with a low risk of cancer, must be considered in the development of array-based assays of variant pathogenicity.
Author Summary
Inherited mutations in the genes BRCA1 and BRCA2 increase risk of breast cancer and contribute to a proportion of breast cancer families. However, more than half of the reported sequence alterations in BRCA1 and BRCA2 are currently of unknown clinical significance. We analysed gene expression in lymphoblastoid cell lines derived from blood of patients with sequence alterations in BRCA1 and BRCA2 and compared these to lymphoblastoid cells from familial breast cancer patients without such alterations. We then classified these lymphoblastoid cells based on their gene profiles. We found that BRCA1 and BRCA2 samples were more similar to each other than to familial breast cancer patients without BRCA1/2 mutations, and that the type of sequence change in BRCA1 and BRCA2 (missense or truncating) influenced gene expression. We included in the study ten familial breast cancer samples, which carried sequence changes in BRCA1 or BRCA2, that are believed to be of little clinical significance. Interestingly these samples were distinct from other familial breast cancer cases without any sequence alteration in BRCA1 or BRCA2, indicating that further work needs to be performed to determine the possible association of these “low clinical significance” sequence changes with a low to moderate risk of cancer.
PMCID: PMC2375115  PMID: 18497862
25.  Genetic variation in insulin-like growth factor signaling genes and breast cancer risk among BRCA1 and BRCA2 carriers 
Women who carry mutations in BRCA1 and BRCA2 have a substantially increased risk of developing breast cancer as compared with the general population. However, risk estimates range from 20 to 80%, suggesting the presence of genetic and/or environmental risk modifiers. Based on extensive in vivo and in vitro studies, one important pathway for breast cancer pathogenesis may be the insulin-like growth factor (IGF) signaling pathway, which regulates both cellular proliferation and apoptosis. BRCA1 has been shown to directly interact with IGF signaling such that variants in this pathway may modify risk of cancer in women carrying BRCA mutations. In this study, we investigate the association of variants in genes involved in IGF signaling and risk of breast cancer in women who carry deleterious BRCA1 and BRCA2 mutations.
A cohort of 1,665 adult, female mutation carriers, including 1,122 BRCA1 carriers (433 cases) and 543 BRCA2 carriers (238 cases) were genotyped for SNPs in IGF1, IGF1 receptor (IGF1R), IGF1 binding protein (IGFBP1, IGFBP2, IGFBP5), and IGF receptor substrate 1 (IRS1). Cox proportional hazards regression was used to model time from birth to diagnosis of breast cancer for BRCA1 and BRCA2 carriers separately. For linkage disequilibrium (LD) blocks with multiple SNPs, an additive genetic model was assumed; and for single SNP analyses, no additivity assumptions were made.
Among BRCA1 carriers, significant associations were found between risk of breast cancer and LD blocks in IGF1R (global P = 0.011 for LD block 2 and global P = 0.012 for LD block 11). Among BRCA2 carriers, an LD block in IGFBP2 (global P = 0.0145) was found to be associated with the time to breast cancer diagnosis. No significant LD block associations were found for the other investigated genes among BRCA1 and BRCA2 carriers.
This is the first study to investigate the role of genetic variation in IGF signaling and breast cancer risk in women carrying deleterious mutations in BRCA1 and BRCA2. We identified significant associations in variants in IGF1R and IRS1 in BRCA1 carriers and in IGFBP2 in BRCA2 carriers. Although there is known to be interaction of BRCA1 and IGF signaling, further replication and identification of causal mechanisms are needed to better understand these associations.
PMCID: PMC2790858  PMID: 19843326

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