Recent studies show that patients with myotonic dystrophy (DM) have an increased risk of specific malignancies, but estimates of absolute cancer risk accounting for competing events are lacking. Using the Swedish Patient Registry, we identified 1,081 patients with an inpatient and/or outpatient diagnosis of DM between 1987 and 2007. Date and cause of death and date of cancer diagnosis were extracted from the Swedish Cause of Death and Cancer Registries. We calculated non-parametric estimates of absolute cancer risk and cancer mortality accounting for the high non-cancer competing mortality associated with DM. Absolute cancer risk after DM diagnosis was 1.6% (95% CI=0.4-4%), 5% (95% CI=3-9%) and 9% (95% CI=6-13%) at ages 40, 50 and 60 years, respectively. Females had a higher absolute risk of all cancers combined than males: 9% (95% CI=4-14), and 13% (95% CI=9-20) vs. 2% (95%CI= 0.7-6) and 4% (95%CI=2-8) by ages 50 and 60 years, respectively) and developed cancer at younger ages (median age =51 years, range=22-74 vs. 57, range=43-84, respectively, p=0.02). Cancer deaths accounted for 10% of all deaths, with an absolute cancer mortality risk of 2% (95%CI=1-4.5%), 4% (95%CI=2-6%), and 6% (95%CI=4-9%) by ages 50, 60, and 70 years, respectively. No gender difference in cancer-specific mortality was observed (p=0.6). In conclusion, cancer significantly contributes to morbidity and mortality in DM patients, even after accounting for high competing DM mortality from non-neoplastic causes. It is important to apply population-appropriate, validated cancer screening strategies in DM patients.
Several common germline variants identified through genome-wide association studies of breast cancer risk in the general population have recently been shown to be associated with breast cancer risk for BRCA1 and/or BRCA2 mutation carriers. When combined, these variants can identify marked differences in the absolute risk of developing breast cancer for mutation carriers, suggesting that additional modifier loci may further enhance individual risk assessment for BRCA1 and BRCA2 mutation carriers. Recently, a common variant on 6p22 (rs9393597) was found to be associated with increased breast cancer risk for BRCA2 mutation carriers [Hazard ratio (HR)=1.55, 95% CI 1.25–1.92, p=6.0×10−5]. This observation was based on data from GWAS studies in which, despite statistical correction for multiple comparisons, the possibility of false discovery remains a concern. Here we report on an analysis of this variant in an additional 6,165 BRCA1 and 3,900 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA). In this replication analysis, rs9393597 was not associated with breast cancer risk for BRCA2 mutation carriers [HR=1.09, 95% CI 0.96–1.24, p=0.18]. No association with ovarian cancer risk for BRCA1 or BRCA2 mutation carriers or with breast cancer risk for BRCA1 mutation carriers was observed. This follow-up study suggests that, contrary to our initial report, this variant is not associated with breast cancer risk among individuals with germline BRCA2 mutations.
BRCA1; BRCA2; genetic modifier; association study
Patients with myotonic dystrophy (DM) have recently been reported to be at increased risk of tumor development, but clinical associations related to this observation are unknown. We calculated the odds ratios (ORs) and 95% confidence intervals (CI) of self-reported tumor development by patients’ demographic and clinical characteristics to evaluate factors associated with tumor development in DM patients, using data from the National Registry of Myotonic Dystrophy and Facioscapulohumeral Dystrophy Patients and Family Members. Of the 911 participants, 47.5% were male and 85.7% had DM type 1 (DM1). Compared with DM1, patients with DM type 2 (DM2) were older at Registry enrollment (median age =55 vs. 44 years, p<0.0001) and at DM diagnosis (median age= 48 vs. 30 years, p<0.0001); and more likely to be females (p=0.001). At enrollment, 95 (10.4%) DM patients reported a history of benign or malignant tumor. Tumors were associated with female gender (OR=1.9, 95% CI=1.2–3.1, p=0.007) and DM1 (OR=2.1, 95% CI=1.1–4.1, p=0.03). In a subgroup analysis of patients with blood-based DNA testing results (397 DM1, 54 DM2), repeat expansion size was not associated with tumor risk in DM1 (p=0.26) or DM2 (p=0.34). In conclusion, female gender and DM1 subtype, but not DNA repeat expansion size, were associated with increased risk of tumors in DM. Follow-up studies are warranted to determine if oncogenes associated with dystrophia myotonica-protein kinase (DMPK) are altered in DM, and to determine if repeat expansion size, as in our study, is not associated with tumor development.
Myotonic dystrophy; comorbidity; neoplasms; risk factors; repeat expansion size
The insulin-like growth factor (IGF) signaling pathway is involved in cell proliferation and differentiation. Elevated serum IGF1 levels have been associated with increased colorectal cancer risk; however, studies of this association with colorectal adenoma are inconclusive. We examined serum IGF1, IGF2, and IGFBP3 levels in relation to risk of advanced colorectal adenoma in a case-control study within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. A total of 764 advanced, left-sided colorectal adenoma cases and 775 controls frequency-matched on gender and ethnicity, without evidence of a left-sided polyp on sigmoidoscopy were included in the current study. Serum levels of IGF1, IGF2, and IGFBP3 were measured using an enzyme linked immunosorbent assay in serum samples collected at baseline. Logistic regression was used to estimate the odds ratios (OR) and 95% confidence intervals (CI) for the associations adjusting for age, race, sex, year of blood draw, body mass index, smoking, and education. Higher IGF1 levels were associated with increased adenoma risk: ORs = 1.58 (95% CI=1.16–2.16), 1.42 (95% CI=1.04–1.93), and 1.80 (95% CI=1.30–2.47) for the second, third, and fourth quartiles, respectively (Ptrend=0.002). Elevated IGF2 levels were also associated with increased adenoma risk (OR=1.43, 95% CI=1.05–1.96 for the fourth vs. first quartile, Ptrend=0.02), but the association was no longer significant after adjustment for IGF1 (Ptrend=0.28). IGFBP3 levels were not associated with adenoma risk. Our analysis showed a significant positive association between circulating IGF1 levels and risk of advanced colorectal adenoma, suggesting that IGF1 is associated with the pivotal precursor to colorectal cancer.
colorectal adenoma; insulin-like growth factor
Recent genomic studies have identified risk SNPs in or near eight genes associated with testicular germ cell tumors (TGCT). Mouse models suggest a role for Dnd1 epigenetics in TGCT susceptibility, and we have recently reported that transgenerational inheritance of epigenetic events may be associated with familial TGCT risk. We now investigate whether aberrant promoter methylation of selected candidate genes is associated with familial TGCT risk. Pyrosequencing assays were designed to evaluate CpG methylation in the promoters of selected genes in peripheral blood DNA from 153 TGCT affecteds and 116 healthy male relatives from 101 multiple-case families. Wilcoxon rank-sum tests and logistic regression models were used to investigate associations between promoter methylation and TGCT. We also quantified gene product expression of these genes, using quantitative PCR. We observed increased PDE11A, SPRY4 and BAK1 promoter methylation, and decreased KITLG promoter methylation, in familial TGCT cases versus healthy male family controls. A significant upward risk trend was observed for PDE11A when comparing the middle and highest tertiles of methylation to the lowest [odds ratio (OR) =1.55, 95% confidence intervals (CI) 0.82-2.93, and 1.94, 95% CI 1.03-3.66], respectively; P
trend=0.042). A significant inverse association was observed for KITLG when comparing the middle and lowest tertiles to the highest (OR=2.15, 95% CI 1.12-4.11, and 2.15, 95% CI 1.12-4.14, respectively; P
trend=0.031). There was a weak inverse correlation between promoter methylation and KITLG expression. Our results suggest that familial TGCT susceptibility may be associated with promoter methylation of previously-identified TGCT risk-modifying genes. Larger studies are warranted.
Promoter methylation; testicular germ cell tumors; familial testicular cancer; epidemiology; candidate gene
To estimate the likely number and predictive strength of cancer-associated single nucleotide polymorphisms (SNPs) that are yet to be discovered for seven common cancers.
From the statistical power of published genome-wide association studies, we estimated the number of undetected susceptibility loci and the distribution of effect sizes for all cancers. Assuming a log-normal model for risks and multiplicative relative risks for SNPs, family history (FH), and known risk factors, we estimated the area under the receiver operating characteristic curve (AUC) and the proportion of patients with risks above risk thresholds for screening. From additional prevalence data, we estimated the positive predictive value and the ratio of non–patient cases to patient cases (false-positive ratio) for various risk thresholds.
Age-specific discriminatory accuracy (AUC) for models including FH and foreseeable SNPs ranged from 0.575 for ovarian cancer to 0.694 for prostate cancer. The proportions of patients in the highest decile of population risk ranged from 16.2% for ovarian cancer to 29.4% for prostate cancer. The corresponding false-positive ratios were 241 for colorectal cancer, 610 for ovarian cancer, and 138 or 280 for breast cancer in women age 50 to 54 or 40 to 44 years, respectively.
Foreseeable common SNP discoveries may not permit identification of small subsets of patients that contain most cancers. Usefulness of screening could be diminished by many false positives. Additional strong risk factors are needed to improve risk discrimination.
In this issue of the journal, Cramer et al. (page XXX) and Zhu et al. (page XXX) report carefully designed phase-3 assessments of candidate ovarian cancer screening biomarkers. The main conclusion is that CA-125 remains the “best of a bad lot”; the new candidates have fallen short of expectations. We review factors impeding the development of an effective ovarian cancer screening strategy, highlight the requirements related to validating proposed screening biomarkers, and emphasize the risks from premature clinical applications of unvalidated tests, all underscoring the need for new research strategies.
Mutations in the BRCA1 gene substantially increase a woman's lifetime risk of breast cancer. However, there is great variation in this increase in risk with several genetic and non-genetic modifiers identified. The BRCA1 protein plays a central role in DNA repair, a mechanism that is particularly instrumental in safeguarding cells against tumorigenesis. We hypothesized that polymorphisms that alter the expression and/or function of BRCA1 carried on the wild-type (non-mutated) copy of the BRCA1 gene would modify the risk of breast cancer in carriers of BRCA1 mutations. A total of 9874 BRCA1 mutation carriers were available in the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) for haplotype analyses of BRCA1. Women carrying the rare allele of single nucleotide polymorphism rs16942 on the wild-type copy of BRCA1 were at decreased risk of breast cancer (hazard ratio 0.86, 95% confidence interval 0.77–0.95, P = 0.003). Promoter in vitro assays of the major BRCA1 haplotypes showed that common polymorphisms in the regulatory region alter its activity and that this effect may be attributed to the differential binding affinity of nuclear proteins. In conclusion, variants on the wild-type copy of BRCA1 modify risk of breast cancer among carriers of BRCA1 mutations, possibly by altering the efficiency of BRCA1 transcription.
BRCA1, a well-known tumor suppressor with multiple interacting partners, is predicted to have diverse biological functions. However, so far its only well-established role is in the repair of damaged DNA and cell cycle regulation. In this regard, the etiopathological study of low-penetrant variants of BRCA1 provides an opportunity to uncover its other physiologically important functions. Using this rationale, we studied the R1699Q variant of BRCA1, a potentially moderate-risk variant, and found that it does not impair DNA damage repair but abrogates the repression of microRNA-155 (miR-155), a bona fide oncomir. Mechanistically, we found that BRCA1 epigenetically represses miR-155 expression via its association with HDAC2, which deacetylates histones H2A and H3 on the miR-155 promoter. We show that overexpression of miR-155 accelerates whereas the knockdown of miR-155 attenuates the growth of tumor cell lines in vivo. Our findings demonstrate a new mode of tumor suppression by BRCA1 and suggest that miR-155 is a potential therapeutic target for BRCA1-deficient tumors.
Environmental exposures, including tobacco smoke and occupational exposure to aromatic amines, have been implicated in bladder cancer etiology. However, the pathogenesis of urinary bladder transitional cell carcinoma remains incompletely defined. In epidemiologic studies, family history confers a two-fold increase in bladder cancer risk, but it is uncertain whether this represents evidence of a genetic and/or a shared environmental basis for familial aggregation. Polymorphisms in genes involved in the metabolism of environmental toxins (e.g., NAT2) clearly modify individual susceptibility to bladder cancer. A genetic predisposition has also been suggested by case reports describing multiple-case families, and the development of bladder cancer in association with several well-described Mendelian disorders (e.g., HNPCC, retinoblastoma). Here we update a previously-reported family, report a new multiple-case kindred, critically review previously-reported bladder cancer families and the epidemiologic literature related to family history of transitional cell carcinoma of the urinary tract (TCCUT) as a risk factor, as well as provide a brief summary of genetic factors that have been implicated in TCCUT risk. We conclude that familial TCCUT is either very uncommon or significantly under-reported, perhaps on the assumption that this is an environmental rather than a genetic disorder. The interaction between multiple genetic and environmental factors has made it challenging to identify genetic components responsible for many common diseases; therefore, a proposed genome-wide association study (GWAS) for urinary bladder cancer may help to clarify the etiologic role of the candidate genetic pathways reviewed here, as well as characterize gene/environment interactions that contribute to TCCUT carcinogenesis.
Urinary bladder neoplasms; transitional cell carcinoma; hereditary neoplastic syndromes; genetic polymorphism
Familial testicular germ cell tumours (TGCTs) and bilateral TGCTs comprise 1–2% and 5% of all TGCTs, respectively, but their genetic basis remains largely unknown.
To investigate the contribution of known testicular cancer risk variants in familial and bilateral TGCTs.
Methods and results
The study genotyped 106 single nucleotide polymorphisms (SNPs) in four regions (BAK1, DMRT1, KITLG, TERT-CLPTM1L) previously identified from genome-wide association studies of TGCT, including risk single nucleotide polymorphisms (SNPs) rs210138 (BAK1), rs755383 (DMRT1), rs4635969 (TERT-CLPTM1L) in 97 cases with familial TGCT and 22 affected individuals with sporadic bilateral TGCT as well as 871 controls. Using a generalised estimating equations method that takes into account blood relationships among cases, the associations with familial and bilateral TGCT were analysed. Three previously identified risk SNPs were found to be associated with familial and bilateral TGCT (rs210138: OR 1.80, CI 1.35 to 2.41, p = 7.03×10−5; rs755383: OR 1.67, CI 1.23 to 2.22, p=6.70×10−4; rs4635969: OR 1.59, CI 1.16 to 2.19, p=4.07×10−3). Evidence for a second independent association was found for an SNP in TERT (rs4975605: OR 1.68, CI 1.23 to 2.29, p=1.24×10−3). Another association with an SNP was identified in KITLG (rs2046971: OR 2.33, p=1.28×10−3); this SNP is in high linkage disequilibrium (LD) with reported risk variant rs995030.
This study provides evidence for replication of recent genome-wide association studies results and shows that variants in or near BAK1, DMRT1, TERT-CLPTM1L, and KITLG predispose to familial and bilateral TGCT. These findings imply that familial TGCT and sporadic TGCT share a common genetic basis.
Knowledge of family cancer history is essential for estimating an individual’s cancer risk and making clinical recommendations regarding screening and referral to a specialty cancer genetics clinic. However, it is not clear if reported family cancer history is sufficiently accurate for this purpose.
In the population-based 2001 Connecticut Family Health Study, 1019 participants reported on 20 578 first-degree relatives (FDR) and second-degree relatives (SDR). Of those, 2605 relatives were sampled for confirmation of cancer reports on breast, colorectal, prostate, and lung cancer. Confirmation sources included state cancer registries, Medicare databases, the National Death Index, death certificates, and health-care facility records. Sensitivity, specificity, positive predictive value, and negative predictive value were calculated for reports on lung, colorectal, breast, and prostate cancer and after stratification by sex, age, education, and degree of relatedness and used to estimate report accuracy. Pairwise t tests were used to evaluate differences between the two strata in each stratified analysis. All statistical tests were two-sided.
Overall, sensitivity and positive predictive value were low to moderate and varied by cancer type: 60.2% and 40.0%, respectively, for lung cancer reports, 27.3% and 53.5% for colorectal cancer reports, 61.1% and 61.3% for breast cancer reports, and 32.0% and 53.4% for prostate cancer reports. Specificity and negative predictive value were more than 95% for all four cancer types. Cancer history reports on FDR were more accurate than reports on SDR, with reports on FDR having statistically significantly higher sensitivity for prostate cancer than reports on SDR (58.9% vs 21.5%, P = .002) and higher positive predictive value for lung (78.1% vs 31.7%, P < .001), colorectal (85.8% vs 43.5%, P = .004), and breast cancer (79.9% vs 53.6%, P = .02).
General population reports on family history for the four major adult cancers were not highly accurate. Efforts to improve accuracy are needed in primary care and other health-care settings in which family history is collected to ensure appropriate risk assessment and clinical care recommendations.
We conducted a meta-analysis to identify new loci for testicular germ cell tumor (TGCT) susceptibility. In the discovery phase, 931 affected individuals and 1,975 controls from three genome wide association studies (GWAS) were analyzed. Replication was conducted in six independent sample sets totaling 3,211 affected individuals and 7,591 controls. In the combined analysis, TGCT risk was significantly associated with markers at four novel loci: 4q22.2 in HPGDS (per allele odds ratio (OR) 1.19, 95%CI 1.12–1.26, P = 1.11×10−8); 7p22.3 in MAD1L1 (OR 1.21, 95%CI 1.14–1.29, P = 5.59×10−9); 16q22.3 in RFWD3 (OR 1.26, 95%CI 1.18–1.34, P = 5.15×10−12); and 17q22 (rs9905704; OR 1.27, 95%CI 1.18–1.33; P = 4.32×10−13, and rs7221274; OR 1.20, 95%CI 1.12–1.28 P = 4.04×10−9), a locus which includes TEX14, RAD51C and PPM1E. The new TGCT susceptibility loci contain biologically plausible genes encoding proteins important for male germ cell development, chromosomal segregation and DNA damage response.
Testicular cancer, while rare compared with other adult solid tumors, is the most common cancer in young men in northern Europe and North America. Risk factors include white race, positive family history, contralateral testicular cancer, cryptorchidism, infertility and testicular microlithiasis. As the genetic causes of familial clusters (Familial Testicular Cancer or FTC) are being sought, it is also important to understand the psycho-social experiences of members of FTC families.
This is a cross-sectional examination via the Colored Eco-Genetic Relationship Map (CEGRM) of social connections reported by 49 men in FTC families participating in NCI research study 02-C-178.
The CEGRM was acceptable and feasible for use with men in FTC families, and valuable in understanding their social connections. These men have largely adjusted to the TC history in themselves and/or their relatives. They have considerable social and emotional support from family and friends, although there is wide variability in sources and types.
The CEGRM focuses on men's social connections and close emotional bonds in FTC families. This action-oriented process of placing colored symbols on significant relationships uncovered previously under-appreciated emotions accompanying men's social exchanges. Most men in FTC families succeed in re-establishing a sense of normalcy in their lives and social connections, in the aftermath of a testicular cancer diagnosis.
Risk-reducing salpingo-oophorectomy (RRSO) is the most definitive surgical intervention for ovarian cancer risk reduction among BRCA1/2 mutation carriers. For women who have completed child-bearing but who are not ready for RRSO, bilateral salpingectomy with ovarian retention (BSOR) might serve as a temporary measure while definitive risk-reducing surgery is being contemplated. Here we summarize recent insights into the pathogenesis of hereditary ovarian cancer which might provide a basis for considering the proposed BSOR management strategy and outline the evidence for and against this potential risk-reducing intervention. Based on the evidence presented, we suggest that there may be sufficient merit in this proposed intervention to consider evaluating it formally, perhaps through an intergroup-based clinical trial. In the meanwhile, we believe that BSOR should be considered an investigational risk management option of unproven clinical utility, particularly since delay in bilateral oophorectomy could theoretically reduce the protective effect against breast cancer that has been documented in women undergoing RRSO.
bilateral oophorectomy; bilateral salpingectomy; BRCA1/2 mutation carriers; ovarian cancer risk; risk-reducing surgery
Women who are genetically predisposed to ovarian cancer are at very high risk of developing this disease. Although risk-reducing salpingo-oophorectomy (RRSO) and various screening regimens are currently recommended to reduce ovarian cancer risk, the optimal management strategy has not been established nor have multiple additional issues been adequately addressed. We developed a collaboration among the Clinical Genetics Branch (National Cancer Institute’s Intramural Research Program), the Gynecologic Oncology Group (GOG), and the Cancer Genetics Network to address these issues.
This is a prospective, international, two-cohort, nonrandomized study of women at genetic risk of ovarian cancer, who chose either to undergo RRSO or screening, at study enrollment. Primary study objectives include quantifying and comparing ovarian and breast cancer incidence in the two study groups, assessing feasibility and selected performance characteristics of a novel ovarian cancer screening strategy (the Risk of Ovarian Cancer Algorithm), evaluating various aspects of quality of life and nononcologic morbidity related to various interventions in at-risk women, and creating a biospecimen repository for subsequent translational research.
Study accrual is complete as of November 2006; 2,605 participants enrolled: 1,030 (40%) into the surgical cohort and 1,575 (60%) into the screening cohort. Five years of prospective follow-up ends in November 2011. Verification of BRCA mutation carrier status is under way, either through patient-provided reports from clinical genetic testing done before enrollment or through research-based genetic testing being conducted as part of the protocol. Patient eligibility is currently under evaluation and baseline, surgical, pathology, and outcome data are still being collected. The study design and selected baseline characteristics of cohort members are summarized.
This National Cancer Institute intramural/extramural collaboration will provide invaluable prospectively collected observational data on women at high familial ovarian cancer risk, including substantial numbers of women carrying BRCA1/2 mutations. These data will aid in elucidating the effect of RRSO on breast/ovarian cancer risk and the effects of two management strategies, on quality of life and other issues that may influence patient care, as well as providing preliminary estimates of test specificity and positive predictive value of a novel ovarian cancer screening strategy.
We investigated the association between psychological distress and indices of social integration and communal coping among sisters from hereditary breast and ovarian cancer (HBOC) families.
Sample and methods
Sixty-five sisters from 31 HBOC families completed the Brief Symptom Inventory-18 and the Colored Eco-Genetic Relationship Map, which identified members of participants’ social support networks. Hierarchical linear models were used for all analyses to account for the clustering of sisters within families.
Intra-family correlation coefficients suggested that sisters shared perceptions of breast cancer risk and worry, but not ovarian cancer risk and worry. Further, sisters demonstrated shared levels of anxiety and somatization, but not depressive symptoms. Communal coping indices quantifying shared support resources were negatively related to anxiety and somatization. The number of persons with whom cancer risk information was shared exhibited a positive trend with somatization. Social integration, as measured by the size of participants’ emotional support network, was negatively associated with anxiety. Lower depression scores were observed among participants with more persons playing multiple support roles and fewer persons providing tangible assistance.
Understanding how support relationships impact well-being among persons adjusting to HBOC risk, and the particular role of family in that process, will facilitate developing appropriate management approaches to help cancer-prone families adjust to their cancer risk. Published in 2008 by John Wiley & Sons Ltd.
social support; communal coping; hereditary breast and ovarian cancer; sisters; psychological distress
Fanconi anaemia (FA), dyskeratosis congenita (DC), Diamond-Blackfan anaemia (DBA), and Shwachman-Diamond syndrome (SDS) comprise major inherited bone marrow failure syndromes (IBMFS). Adverse events include severe bone marrow failure (BMF), myelodysplastic syndrome (MDS), acute myeloid leukaemia (AML), and solid tumours (ST). The natural history of FA is well characterised; hazard rates in the other syndromes have not yet been quantified. An open cohort was established at the National Cancer Institute (NCI) in 2002. Patients enrolled prior to December, 2007 were followed up to December, 2008. Diagnoses were confirmed with standard tests. Age-associated risks of adverse events were calculated. Most patients in each syndrome survived to young adulthood. Patients with FA had earlier onset of cancers, need for stem cell transplant, and death; followed by DC; DBA and SDS were mildest. While FA and DC patients had markedly increased risks of cancer, AML and MDS, there were no cases of leukaemia in DBA or SDS patients. The NCI cohort provides the first direct quantitative comparison of timing and magnitude of cancer risk in the IBMFS. The findings demonstrate that both FA and DC are major cancer susceptibility syndromes. The IBMFS, historically considered paediatric disorders, have important management implications for physicians treating adult patients.
bone marrow failure; Fanconi anaemia; dyskeratosis congenita; leukaemia; solid tumours
We develop methods for competing risks analysis when individual event times are correlated within clusters. Clustering arises naturally in clinical genetic studies and other settings. We develop a nonparametric estimator of cumulative incidence, and obtain robust pointwise standard errors that account for within-cluster correlation. We modify the two-sample Gray and Pepe–Mori tests for correlated competing risks data, and propose a simple two-sample test of the difference in cumulative incidence at a landmark time. In simulation studies, our estimators are asymptotically unbiased, and the modified test statistics control the type I error. The power of the respective two-sample tests is differentially sensitive to the degree of correlation; the optimal test depends on the alternative hypothesis of interest and the within-cluster correlation. For purposes of illustration, we apply our methods to a family-based prospective cohort study of hereditary breast/ovarian cancer families. For women with BRCA1 mutations, we estimate the cumulative incidence of breast cancer in the presence of competing mortality from ovarian cancer, accounting for significant within-family correlation.
BRCA1 gene; Breast neoplasm; Competing risks; Correlated survival data; Counting processes; Robust variance
In this review, we define familial testicular germ cell tumors (FTGCT) as testicular germ cell tumors (TGCT) diagnosed in at least two blood relatives, a situation which occurs in 1-2% of all cases of TGCT. Brothers and fathers of TGCT patients have an 8-10 and 4-6 fold increased risk of TGCT, respectively, and an even higher elevated risk of TGCT in twin brothers of men with TGCT has been observed, suggesting that genetic elements play an important role in these tumors. Nevertheless, previous linkage studies with multiple FTGCT families did not uncover any high-penetrance genes and it has been concluded that the combined effects of multiple common alleles, each conferring modest risk, might underlie FTGCT. In agreement with this assumption, recent candidate gene association analyses have identified the chromosome Y gr/gr deletion and mutations in the PDE11A gene as genetic modifiers of FTGCT risk. Moreover, two genomewide association studies of predominantly sporadic but also familial cases of TGCT have identified three additional susceptibility loci, KITLG, SPRY4 and BAK1. Notably, all five loci are involved in the biology of primordial germ cells, representing the cell of origin of TGCT, suggesting that the tumors arise as a result of disturbed testicular development.
Familial testicular cancer germ cell tumors; genetic susceptibility; KITLG-KIT signaling
Although family history of cancer is widely ascertained in research and clinical care, little is known about assessment methods, accuracy, or other quality measures. Given its widespread use in cancer screening and surveillance, better information is needed regarding the clarity and accuracy of family history information reported in the general population.
This telephone survey in Connecticut examined coherence and completeness of reports from 1,019 respondents about 20,504 biological relatives.
Of 2,657 cancer reports, 97.7% were judged consistent with malignancy (vs. benign or indeterminate conditions); 79% were site-specific, 10.8% had unspecified cancer sites and 8.6% had “ill-defined” sites. Only 6.1% of relatives had unknown histories. Unknown histories and ambiguous sites were significantly higher for second-degree relatives. The adjusted percentage of first-degree relative reports with ambiguous sites increased with decreasing education and African-American race of survey respondents, and with deceased vital status of relatives. Ambiguous second-degree relative reports were also associated with deceased vital status, and with male gender of respondents.
These findings suggest that family history of cancer reports from the general population are generally complete and coherent.
Strategies are needed to improve site specificity and thus maximize the utility of such information in primary care settings.
family history of cancer; quality; methods; assessment; population-based; survey research
Familial aggregations of testicular germ cell tumor (FTGCT) have been well described, suggesting the existence of a hereditary TGCT subset. Approximately 1.4% of newly diagnosed TGCT patients report a positive family history of TGCT. Sons and siblings of TGCT patients have four- to sixfold and eight- to tenfold increases in TGCT risk respectively. Segregation analyses suggest an autosomal recessive mode of inheritance. Linkage analyses have identified several genomic regions of modest interest, although no high-penetrance cancer susceptibility gene has been mapped yet. These data suggest that the combined effects of multiple common alleles, each conferring modest risk, might underlie familial testicular cancer. Families display a mild phenotype: the most common number of affected families is 2. Age at diagnosis is 2–3 years younger for familial versus sporadic cases. The ratio of familial seminoma to nonseminoma is 1.0. FTGCT is more likely to be bilateral than sporadic TGCT. This syndrome is cancer site specific. Testicular microlithiasis is a newly recognized FTGCT component. Candidate gene-association studies have implicated the Y chromosome gr/gr deletion and PDE11A gene mutations as genetic modifiers of FTGCT risk. Two genomewide association studies of predominantly sporadic but also familial cases of TGCT have implicated the KIT-ligand, SPRY4, and BAK1 genes as TGCT risk modifiers. All five loci are involved in normal testicular development and/or male infertility. These genetic data provide a novel insight into the genetic basis of FTGCT, and an invaluable guide to future TGCT research.
Tamoxifen was approved for breast cancer risk reduction in high-risk women based on the National Surgical Adjuvant Breast and Bowel Project's Breast Cancer Prevention Trial (P-1:BCPT), which showed 50% fewer breast cancers with tamoxifen versus placebo, supporting tamoxifen's efficacy in preventing breast cancer. Poor metabolizing CYP2D6 variants are currently the subject of intensive scrutiny regarding their impact on clinical outcomes in the adjuvant setting. Our study extends to variants in a wider spectrum of tamoxifen-metabolizing genes and applies to the prevention setting.
Our case-only study, nested within P-1:BCPT, explored associations of polymorphisms in estrogen/tamoxifen-metabolizing genes with responsiveness to preventive tamoxifen. Thirty-nine candidate polymorphisms in 17 candidate genes were genotyped in 249 P-1:BCPT cases.
CYP2D6_C1111T, individually and within a CYP2D6 haplotype, showed borderline significant association with treatment arm. Path analysis of the entire tamoxifen pathway gene network showed that the tamoxifen pathway model was consistent with the pattern of observed genotype variability within the placebo-arm dataset. However, correlation of variations in genes in the tamoxifen arm differed significantly from the predictions of the tamoxifen pathway model. Strong correlations between allelic variation in the tamoxifen pathway at CYP1A1-CYP3A4, CYP3A4-CYP2C9, and CYP2C9-SULT1A2, in addition to CYP2D6 and its adjacent genes, were seen in the placebo-arm but not the tamoxifen-arm. In conclusion, beyond reinforcing a role for CYP2D6 in tamoxifen response, our pathway analysis strongly suggests that specific combinations of allelic variants in other genes make major contributions to the tamoxifen-resistance phenotype.
Breast cancer; tamoxifen resistance; chemoprevention; pathway analysis; breast cancer risk; genomic polymorphisms