Self-rated health (SRH), a consistent predictor of mortality among diverse populations, is sensitive to health indicators and social factors. American-born Hispanics report better SRH than their foreign-born counterparts but simultaneously report poorer health indicators and have shorter life expectancy. Using a matched prospective cross-sectional design, we analyzed data from 631 age-matched pairs of women, born in the United States or Mexico, enrolled in a cohort study based in Houston, Texas. Our first goal was to describe the relationships between SRH and health behaviors, physician-diagnosed chronic conditions, acculturation, and socioeconomic status (SES) by birthplace. Our second goal was to investigate the relative influence of SES, acculturation, health behaviors, and physician-diagnosed conditions in explaining expected differences in SRH between the two groups. Number of chronic conditions reported, particularly depression, more strongly influenced SRH than SES, acculturation, or reported health risk behaviors and the influence of birthplace is accounted for by these factors.
Self-rated health; acculturation; SES; health indicators
The authors have recently shown that a majority of patients with myelodysplastic syndrome (MDS) classified by the International Prognostic Scoring System as lower risk die without transformation to acute myelogenous leukemia (AML). The cause of death (COD) of these patients is not well understood. Identifying the COD could help to guide early therapy decisions.
The authors retrospectively analyzed the COD in a cohort of 273 deceased patients with lower-risk MDS according to the International Prognostic Scoring System at presentation to The University of Texas M. D. Anderson Cancer Center from 1980 to 2004. MDS-related death was defined as infection, bleeding, transformation to AML, or disease progression. Remaining CODs were classified as non–MDS-related.
Median age at presentation was 66 years (range, 19-88 years). Overall median survival was 59 weeks (range, 1-831 weeks). All French-American-British leukemia classification subgroups were represented. The percentage of International Prognostic Scoring System low and intermediate-1 groups were 21% and 79%, respectively. The most common cytogenetic abnormality (9%) was del(5q). Patients received supportive care only. The COD was identified as MDS-related in 230 of 273 (84%) patients. The most common disease-related CODs were infection (38%), transformation to AML (15%), and hemorrhage (13%). The most frequent non–disease-related COD was cardiovascular events (19 of 43 patients).
The majority of patients with low- or intermediate-1 risk MDS will die because of causes related to their underlying disease. Although these results need to be validated in different populations, early therapeutic intervention could be considered in the management of these patients to improve survival.
myelodysplastic syndrome; mortality; International Prognostic Scoring System; cause of death
Owing to their role in controlling the efflux of toxic compounds, transporters are central players in the process of detoxification and elimination of xenobiotics, which in turn is related to cancer risk. Among these transporters, ATP-binding cassette B1/multidrug resistance 1 (ABCB1/MDR1), ABCC2/multidrug resistance protein 2 (MRP2), and ABCG2/breast cancer resistance protein (BCRP) affect susceptibility to many hematopoietic malignancies. The maintenance of regulated expression of these transporters is governed through the activation of intracellular “xenosensors” like the nuclear receptor 1I2/pregnane X receptor (NR1I2/PXR). SNPs in genes encoding these regulators have also been implicated in the risk of several cancers. Using a tagging approach, we tested the hypothesis that common polymorphisms in the transporter genes ABCB1, ABCC2, ABCG2, and the regulator gene NR1I2 could be implicated in lymphoma risk. We selected 68 SNPs in the 4 genes, and we genotyped them in 1,481 lymphoma cases and 1,491 controls of the European cases-control study (EpiLymph) using the Illumina™ GoldenGate assay technology.Carriers of the SNP rs6857600 minor allele in ABCG2, was associated with a decrease in risk of B-cell lymphoma (B-NHL) overall (p<0.001). Furthermore, a decreased risk of chronic lymphocytic leukemia (CLL) was associated with the ABCG2 rs2231142 variant (p=0.0004), which could be replicated in an independent population. These results suggest a role for this gene in B-NHL susceptibility, especially for CLL.
Lymphoma; multidrug resistance 1 (MDR1); multidrug resistance protein 2 (MRP2); breast cancer resistance protein (BCRP); pregnane X receptor (PXR)
Central obesity, measured by waist circumference (WC) or waist-hip ratio (WHR), is a marker of body fat distribution. Although obesity disproportionately affects minority populations, few studies have conducted genome-wide association study (GWAS) of fat distribution among those of predominantly African ancestry (AA). We performed GWAS of WC and WHR, adjusted and unadjusted for BMI, in up to 33,591 and 27,350 AA individuals, respectively. We identified loci associated with fat distribution in AA individuals using meta-analyses of GWA results for WC and WHR (stage 1). Overall, 25 SNPs with single genomic control (GC)-corrected p-values<5.0×10−6 were followed-up (stage 2) in AA with WC and with WHR. Additionally, we interrogated genomic regions of previously identified European ancestry (EA) WHR loci among AA. In joint analysis of association results including both Stage 1 and 2 cohorts, 2 SNPs demonstrated association, rs2075064 at LHX2, p = 2.24×10−8 for WC-adjusted-for-BMI, and rs6931262 at RREB1, p = 2.48×10−8 for WHR-adjusted-for-BMI. However, neither signal was genome-wide significant after double GC-correction (LHX2: p = 6.5×10−8; RREB1: p = 5.7×10−8). Six of fourteen previously reported loci for waist in EA populations were significant (p<0.05 divided by the number of independent SNPs within the region) in AA studied here (TBX15-WARS2, GRB14, ADAMTS9, LY86, RSPO3, ITPR2-SSPN). Further, we observed associations with metabolic traits: rs13389219 at GRB14 associated with HDL-cholesterol, triglycerides, and fasting insulin, and rs13060013 at ADAMTS9 with HDL-cholesterol and fasting insulin. Finally, we observed nominal evidence for sexual dimorphism, with stronger results in AA women at the GRB14 locus (p for interaction = 0.02). In conclusion, we identified two suggestive loci associated with fat distribution in AA populations in addition to confirming 6 loci previously identified in populations of EA. These findings reinforce the concept that there are fat distribution loci that are independent of generalized adiposity.
Central obesity is a marker of body fat distribution and is known to have a genetic underpinning. Few studies have reported genome-wide association study (GWAS) results among individuals of predominantly African ancestry (AA). We performed a collaborative meta-analysis in order to identify genetic loci associated with body fat distribution in AA individuals using waist circumference (WC) and waist to hip ratio (WHR) as measures of fat distribution, with and without adjustment for body mass index (BMI). We uncovered 2 genetic loci potentially associated with fat distribution: LHX2 in association with WC-adjusted-for-BMI and at RREB1 for WHR-adjusted-for-BMI. Six of fourteen previously reported loci for waist in EA populations were significant in AA studied here (TBX15-WARS2, GRB14, ADAMTS9, LY86, RSPO3, ITPR2-SSPN). These findings reinforce the concept that there are loci for body fat distribution that are independent of generalized adiposity.
This study was conducted to explore whether racial/ethnic differences exist in treatment discussed, preferred and ultimately received for localized PCa as epidemiological data are scant on this issue. We recruited 640 localized PCa patients from the Texas Medical Center, Houston, TX, between 1996 and 2004. We used a structured questionnaire to collect data through personal interviews. Three main treatment modalities for localized PCa, consisting of surgery, radiation therapy and watchful waiting, were considered for this study. We found that health professionals were less likely to discuss surgery (OR=0.35, 95% CI= 0.18–0.68) and watchful waiting (OR=0.53, 95% CI= 0.34–0.83) with Hispanics than whites. Whereas, African Americans were less likely to receive watchful waiting (OR=0.22, 95% CI= 0.05–0.93). They were more likely to prefer (OR=1.23, 95% CI= 0.78–1.94) and receive (OR=1.27, 95% CI= 0.87–1.86) radiation therapy, although, they didn’t achieve statistical significance (p<.05). Higher age was associated with lower likelihood of discussing, preferring and receiving surgical treatment. Higher Gleason sum was associated with lower likelihood of discussing treatment. A comparison of concordances between treatment preferred by patients and what was actually received, in general, showed a higher agreement for surgery and radiation therapy. Watchful waiting was discussed less often (p<.05) with Hispanics and surgical treatment was received less often (p<.05) by African-Americans. More exploration needs to be done in other settings to confirm these findings.
Race/ethnicity; Disparities; Treatment; Prostate; Cancer
Androgen levels during critical periods of testicular development may be involved in the etiology of testicular germ cell tumors (TGCT). We evaluated the roles of adolescent and early adult life correlates of androgen exposure and TGCT in a hospital-based case control study. TGCT cases (n=187) and controls (n=148), matched on age, race and state of residence, participated in the study. Unconditional logistic regression was used to estimate associations between TGCT and male pattern baldness, severe acne, markers of puberty onset and body size. Cases were significantly less likely to report hair loss than controls (OR, 0.6; 95% CI, 0.4, 1.0). Amount of hair loss, increasing age at onset and increasing rate of loss were all inversely associated with TGCT (rate of hair loss: p-trend=0.03; age at onset: p-trend=0.03; amount of hair loss: p-trend=0.01). History of severe acne was inversely associated with TGCT (OR, 0.5; 95% CI, 0.3, 0.9) and height was positively associated with TGCT (p-trend=0.02). Increased endogenous androgen levels during puberty and early adulthood may be associated with decreased risk of TGCT. Additional studies of endogenous hormone levels during puberty and early adult life are warranted, especially studies evaluating the role of androgen synthesis, metabolism and uptake.
Testicular germ cell tumors; baldness; acne; hospital-based; case-control
Prostate cancer (CaP) is the leading cancer among men of African descent in the USA, Caribbean, and Sub-Saharan Africa (SSA). The estimated number of CaP deaths in SSA during 2008 was more than five times that among African Americans and is expected to double in Africa by 2030. We summarize publicly available CaP data and collected data from the men of African descent and Carcinoma of the Prostate (MADCaP) Consortium and the African Caribbean Cancer Consortium (AC3) to evaluate CaP incidence and mortality in men of African descent worldwide. CaP incidence and mortality are highest in men of African descent in the USA and the Caribbean. Tumor stage and grade were highest in SSA. We report a higher proportion of T1 stage prostate tumors in countries with greater percent gross domestic product spent on health care and physicians per 100,000 persons. We also observed that regions with a higher proportion of advanced tumors reported lower mortality rates. This finding suggests that CaP is underdiagnosed and/or underreported in SSA men. Nonetheless, CaP incidence and mortality represent a significant public health problem in men of African descent around the world.
Clonal mosaicism for large chromosomal anomalies (duplications, deletions and uniparental disomy) was detected using SNP microarray data from over 50,000 subjects recruited for genome-wide association studies. This detection method requires a relatively high frequency of cells (>5–10%) with the same abnormal karyotype (presumably of clonal origin) in the presence of normal cells. The frequency of detectable clonal mosaicism in peripheral blood is low (<0.5%) from birth until 50 years of age, after which it rises rapidly to 2–3% in the elderly. Many of the mosaic anomalies are characteristic of those found in hematological cancers and identify common deleted regions that pinpoint the locations of genes previously associated with hematological cancers. Although only 3% of subjects with detectable clonal mosaicism had any record of hematological cancer prior to DNA sampling, those without a prior diagnosis have an estimated 10-fold higher risk of a subsequent hematological cancer (95% confidence interval = 6–18).
DNA repair variants may play a potentially important role in an individual’s susceptibility to developing cancer. Numerous studies have reported the association between genetic single nucleotide polymorphisms (SNPs) in DNA repair genes and different types of hematologic cancers. However, to date, the effects of such SNPs on modulating Hodgkin Lymphoma (HL) risk have not yet been investigated. We hypothesized that gene-gene interaction between candidate genes in Direct Reversal, Nucleotide excision repair (NER), Base excision repair (BER) and Double strand break (DSB) pathways may contribute to susceptibility to HL. To test this hypothesis, we conducted a study on 200 HL cases and 220 controls to assess associations between HL risk and 21 functional SNPs in DNA repair genes. We evaluated potential gene-gene interactions and the association of multiple polymorphisms in a chromosome region using a multi-analytic strategy combining logistic regression, multi-factor dimensionality reduction and classification and regression tree approaches. We observed that, in combination, allelic variants in the XPC Ala499Val, NBN Glu185Gln, XRCC3 Thr241Me, XRCC1 Arg194Trp and XRCC1 399Gln polymorphisms modify the risk for developing HL. Moreover, the cumulative genetic risk score revealed a significant trend where the risk for developing HL increases as the number of adverse alleles in BER and DSB genes increase. These findings suggest that DNA repair variants in BER and DSB pathways may play an important role in the development of HL.
This study was carried out to identify racial/ethnic differences in predictors of prostate-specific antigen (PSA) screening in a group of prostate cancer patients.
In this cross-sectional study, a total of 935 prostate cancer patients were recruited from the Texas Medical Center, Houston, between 1996 and 2004. It included 372 Caucasians, 346 African Americans and 217 Hispanics. A structured questionnaire was used to collect data on socio-demographic and life-style related variables, and self-reported PSA screening history through personal interview.
African American (54.4%) and Hispanic patients (42.3%) were significantly less likely (p=0.004 and p<0.001, respectively) to report having had PSA screening than Caucasian patients (63.2%). Only annual check-up was found to be a significant predictor of PSA screening in Hispanics. Among Caucasians, education and annual check-up were significant predictors of PSA screening; whereas in African Americans, education, annual check-up, marital status and BMI were significant predictors of PSA screening.
The rates of PSA screening and its predictors varied by race/ethnicity in this tri-ethnic population. Health-education programs and culturally appropriate educational outreach efforts, especially targeted for high-risk groups, are needed to reduce these disparities.
PSA; screening; predictors; race; disparity
Monoclonal B cell lymphocytosis (MBL) is a hematologic condition wherein small B cell clones can be detected in the blood of asymptomatic individuals. Most MBL have an immunophenotype similar to chronic lymphocytic leukemia (CLL), and “CLL-like” MBL is a precursor to CLL. We used flow cytometry to identify MBL from unaffected members of CLL kindreds. We identified 101 MBL cases from 622 study subjects; of these, 82 individuals with MBL were further characterized. Ninety-one unique MBL clones were detected: 73 CLL-like MBL (CD5+CD20dimsIgdim), 11 atypical MBL (CD5+CD20+sIg+), and 7 CD5neg MBL (CD5negCD20+sIgneg). Extended immunophenotypic characterization of these MBL subtypes was performed, and significant differences in cell surface expression of CD23, CD49d, CD79b, and FMC-7 were observed among the groups. Markers of risk in CLL such as CD38, ZAP70, and CD49d were infrequently expressed in CLL-like MBL, but were expressed in the majority of atypical MBL. Interphase cytogenetics was performed in 35 MBL cases, and del 13q14 was most common (22/30 CLL-like MBL cases). Gene expression analysis using oligonucleotide arrays was performed on 7 CLL-like MBL, and showed activation of B cell receptor associated pathways. Our findings underscore the diversity of MBL subtypes and further clarify the relationship between MBL and other lymphoproliferative disorders.
Since the early 1970's the incidence of testicular germ cell tumors (TGCT) in the U.S. has been increasing, however, potential environmental exposures accounting for this rise have not been identified. A prior study reported a significant association among frequent and long-term current users of marijuana and TGCT risk. We aimed to evaluate the relationship of marijuana use and TGCT in a hospital-based case-control study conducted at The University of Texas M. D. Anderson Cancer Center.
TGCT cases diagnosed between January 1990 and October 1996 (n=187) and male friend controls (n=148) were enrolled in the study. All participants were between the ages of 18 and 50 at the time of cases' diagnosis and resided in Texas, Louisiana, Arkansas, or Oklahoma. Associations of marijuana use and TGCT were estimated using unconditional logistic regression, adjusting for age, race, prior cryptorchidism, cigarette smoking and alcohol intake.
Overall, TGCT cases were more likely to be frequent marijuana users (daily or greater) than were controls [OR: 2.2, 95% CI: 1.0, 5.1]. In the histologic-specific analyses nonseminoma cases were significantly more likely than controls to be frequent users [OR: 3.1, 95% CI: 1.2, 8.2] and long-term users (10+ years) [OR: 2.4, 95% CI: 1.0, 6.1].
Our finding of an association between frequent marijuana use and TGCT, particularly among men with nonseminoma, is consistent with the findings of a previous report. Additional studies of marijuana use and TGCT are warranted, especially studies evaluating the role of endocannabinoid signaling and cannabinoid receptors in TGCT.
marijuana use; seminomas; nonseminomas; testicular germ cell tumors; hospital-based case-control
In search of common risk alleles for prostate cancer that could contribute to high rates of the disease in men of African ancestry, we conducted a genome-wide association study (GWAS), with 1,047,986 single nucleotide polymorphism (SNP) markers examined in 3,425 African American prostate cancer cases and 3,290 African American male controls. The most significant 17 novel associations in stage 1 were followed-up in 1,844 cases and 3,269 controls of African ancestry. We identified a novel risk variant on chromosome 17q21 (rs7210100; odds ratio per allele=1.51; p=3.4×10−13). The frequency of the risk allele is ~5% in men of African descent while it is rare in other populations (<1%). Further studies are needed to investigate the biological contribution of this allele to prostate cancer risk. These findings emphasize the importance of conducting GWAS in diverse populations.
The incidence of nonmelanoma skin cancer (NMSC) is equivalent to that of all other cancers combined. Previously, we mapped the 12-O-tetradecanoylphorbol-13-acetate (TPA) skin tumor promotion susceptibility locus, Psl1, to distal chromosome 9 in crosses of sensitive DBA/2 mice with relatively resistant C57BL/6 mice. Here, we used the mouse two-stage skin carcinogenesis model to identify the gene(s) responsible for the effects of Psl1.
Interval-specific congenic mouse strains (n ≥ 59 mice per strain) were used to more precisely map the Psl1 locus. Having identified glutathione S-transferase α4 (Gsta4) as a candidate tumor promotion susceptibility gene that mapped within the delimited region, we analyzed Gsta4-deficient mice (n = 62) for susceptibility to skin tumor promotion by TPA. We used quantitative polymerase chain reaction, western blotting, and immunohistochemistry to verify induction of Gsta4 in mouse epidermis following TPA treatment and biochemical assays to associate Gsta4 activity with tumor promotion susceptibility. In addition, single-nucleotide polymorphisms (SNPs) in GSTA4 were analyzed in a case–control study of 414 NMSC patients and 450 control subjects to examine their association with human NMSC. Statistical analyses of tumor studies in mice were one-sided, whereas all other statistical analyses were two-sided.
Analyses of congenic mice indicated that at least two loci, Psl1.1 and Psl1.2, map to distal chromosome 9 and confer susceptibility to skin tumor promotion by TPA. Gsta4 maps to Psl1.2 and was highly induced (mRNA and protein) in the epidermis of resistant C57BL/6 mice compared with that of sensitive DBA/2 mice following treatment with TPA. Gsta4 activity levels were also higher in the epidermis of C57BL/6 mice following treatment with TPA. Gsta4-deficient mice (C57BL/6.Gsta4-/- mice) were more sensitive to TPA skin tumor promotion (0.8 tumors per mouse vs 0.4 tumors per mouse in wild-type controls; difference = 0.4 tumors per mouse; 95% confidence interval = 0.1 to 0.7, P = .007). Furthermore, inheritance of polymorphisms in GSTA4 was associated with risk of human NMSC. Three SNPs were found to be independent predictors of NMSC risk. Two of these were associated with increased risk of NMSC (odds ratios [ORs] = 1.60 to 3.42), while the third was associated with decreased risk of NMSC (OR = 0.63). In addition, a fourth SNP was associated with decreased risk of basal cell carcinoma only (OR = 0.44).
Gsta4/GSTA4 is a novel susceptibility gene for NMSC that affects risk in both mice and humans.
Monoclonal B-cell lymphocytosis (MBL) is an asymptomatic haematological condition characterized by low absolute levels of B-cell clones with a surface immunophenotype similar to that of chronic lymphocytic leukaemia (CLL). In the general population, MBL increases with age with a prevalence of 5–9% in individuals over age 60 years. It has been reported to be higher among first-degree relatives from CLL families. We report results of multi-parameter flow cytometry among 505 first-degree relatives with no personal history of lymphoproliferative disease from 140 families having at least two cases of CLL. Seventeen percent of relatives had MBL. Age was the most important determinant where the probability for developing MBL by age 90 years was 61%. MBL clustered in certain families but clustering was independent of the number of known CLL cases in a family. As is the case with CLL, males had a significantly higher risk for MBL than did females (p=0.04). MBL patients had significantly higher mean absolute lymphocyte counts (2.4 × 109/l) and B-cell counts (0.53 × 109/l) than those with a normal B-cell immunophenotype. Our findings show that MBL occurs at a very high rate in high risk CLL families. Both the age and gender distribution of MBL are parallel to CLL, implying a shared inherited risk.
chronic lymphocytic leukaemia; high risk families; monoclonal B-cell lymphocytosis; flow cytometry
Genome-wide association studies (GWAS) have identified numerous prostate cancer susceptibility alleles, but these loci have been identified primarily in men of European descent. There is limited information about the role of these loci in men of African descent.
We identified 7,788 prostate cancer cases and controls with genotype data for 47 GWAS-identified loci.
We identified significant associations for SNP rs10486567 at JAZF1, rs10993994 at MSMB, rs12418451 and rs7931342 at 11q13, and rs5945572 and rs5945619 at NUDT10/11. These associations were in the same direction and of similar magnitude as those reported in men of European descent. Significance was attained at all report prostate cancer susceptibility regions at chromosome 8q24, including associations reaching genome-wide significance in region 2.
We have validated in men of African descent the associations at some, but not all, prostate cancer susceptibility loci originally identified in European descent populations. This may be due to heterogeneity in genetic etiology or in the pattern of genetic variation across populations.
The genetic etiology of prostate cancer in men of African descent differs from that of men of European descent.
prostate cancer; genetic susceptibility; men of African descent
GWAS of prostate cancer have been remarkably successful in revealing common genetic variants and novel biological pathways that are linked with its etiology. A more complete understanding of inherited susceptibility to prostate cancer in the general population will come from continuing such discovery efforts and from testing known risk alleles in diverse racial and ethnic groups. In this large study of prostate cancer in African American men (3,425 prostate cancer cases and 3,290 controls), we tested 49 risk variants located in 28 genomic regions identified through GWAS in men of European and Asian descent, and we replicated associations (at p≤0.05) with roughly half of these markers. Through fine-mapping, we identified nearby markers in many regions that better define associations in African Americans. At 8q24, we found 9 variants (p≤6×10−4) that best capture risk of prostate cancer in African Americans, many of which are more common in men of African than European descent. The markers found to be associated with risk at each locus improved risk modeling in African Americans (per allele OR = 1.17) over the alleles reported in the original GWAS (OR = 1.08). In summary, in this detailed analysis of the prostate cancer risk loci reported from GWAS, we have validated and improved upon markers of risk in some regions that better define the association with prostate cancer in African Americans. Our findings with variants at 8q24 also reinforce the importance of this region as a major risk locus for prostate cancer in men of African ancestry.
Prostate cancer is one of the most common cancers in men and is especially frequent in men of African origin, as incidence rates in African Americans in the United States are >1.5–fold greater than rates in European Americans. In order to gain a more complete understanding of the genetic basis of inherited susceptibility to prostate cancer in men of African origin, we examined the associations at risk loci identified in men of European and Asian descent in a large African American sample of 3,425 cases of prostate cancer and 3,290 male controls. In testing 49 known risk variants, we were able to demonstrate that at least half of these variants also contribute to risk in African American men. We were able to find additional risk variants in many of the previously reported regions that better captured the pattern of risk in African American men. In addition, we verified and improved upon the evidence we previously reported that there are multiple risk variants in a region of 8q24 that are important in men of African origin.
There is strong and consistent evidence that a genetic component contributes to the etiology of chronic lymphocytic leukemia (CLL). A recent genome-wide association study (GWAS) of CLL identified 7 genetic variants that increased the risk of CLL within a European population.
We evaluated the association of these variants, or variants in linkage disequilibrium (LD) with these variants, with CLL risk in an independent sample of 438 CLL cases and 328 controls.
Of these 7 SNPs, 6 had p-trend < 0.05 and had estimated odds ratios (ORs) that were strikingly comparable to those of the previous study. Associations were seen for rs9378805 (OR = 1.47, 95% CI: 1.19, 1.80, p-trend = 0.0003) near IRF4 and rs735665 near GRAMD1B (OR= 1.47; 95% CI: 1.14, 1.89; p-trend = 0.003). However, no associations (P> 0.05) were found for rs11083846, nor were any found for any SNPs in LD with rs11083846.
Our results confirm the previous findings and further support the role of a genetic basis in the etiology of CLL; however, more research is needed to elucidate the causal SNP(s) and the potential manner in which these SNPs or linked SNPs function in CLL pathogenesis.
IRF4; CLL; genetic association
Although cigarette smoking and alcohol use are known risk factors for squamous cell carcinoma of head and neck (SCCHN), only a few exposed individuals develop this disease, suggesting an individual susceptibility. In this study, we investigated the associations between genetically determined DNA repair capacity (DRC) for removing tobacco-induced DNA adducts and risk of SCCHN and tumor characteristics.
We measured DRC in cultured T-lymphocytes using the host-cell reactivation assay in a hospital-based case-control study of 744 SCCHN patients and 753 age-, sex-and ethnicity-matched cancer-free controls recruited from The University of Texas M. D. Anderson Cancer Center.
Patients with SCCHN had significantly lower mean DRC (8.84% ± 2.68%) than controls (9.97% ± 2.61%) (P < 0.0001), and the difference accounted for approximately 2-fold increased risk of SCCHN (adjusted odds ratio [OR], 1.91; 95% CI, 1.52–2.40) after adjustment for other covariates. Compared with the highest DRC quartile of controls, this increased risk was dose-dependent (second highest quartile: OR, 1.40; 95% CI, 0.99–1.98; third quartile: OR, 1.87; 95% CI, 1.34–2.62; and fourth quartile: OR, 2.76; 95% CI, 1.98–3.84, respectively; Ptrend < 0.0001). We also assessed the performance of DRC in risk prediction models by calculating the area of under the receiver operating characteristic curve. The addition of DRC to the model significantly improved the sensitivity of the expanded model. However, we did not find the association between DRC and tumor sites and stages.
DRC is an independent susceptibility biomarker for SCCHN risk but not a tumor marker.
nucleotide excision repair; genetic susceptibility; head and neck neoplasm; molecular epidemiology
Acute Myeloid Leukemia (AML) is frequently associated with genetic abnormalities. Based on pre-treatment cytogenetics, patients are classified into favorable, intermediate and poor subgroups. Cytogenetics predicts treatment outcome for the favorable and poor subgroups but not for the intermediate subgroup. Polymorphisms within the nucleotide excision repair (NER) pathway may lead to inter-individual differences in DNA repair capacity (DRC) which could influence outcome.
We studied the role of 6 polymorphisms (ERCC1 Gln504Lys, XPD Lys751Gln, XPC Ala499Val, XPC Lys939Gln, XPG Asp1104His, and CCNH Val270Ala) within NER pathway on overall and disease-free survival among 170 adult de-novo AML patients with intermediate cytogenetics [diploid (n=117); non-diploid (n=53)], treated with induction chemotherapy. Kaplan-Meier methods and Cox proportional hazards models were performed.
Diploid patients with the XPD AC/CC genotype survived shorter than those with the wild-type (AA) genotype (median survival 22 vs. 40 months, log-rank p = 0.03). Similarly diploid patients with XPC CT/TT genotype survived shorter than those with the wild-type (CC) genotype (median survival 15 vs. 30 months, log-rank p = 0.02). Among diploid patients, after adjusting for clinical and socio-demographic variables, patients carrying both XPD AC/CC and XPC CT/TT had a greater than two-fold increased risk of dying compared to those with the wild-type genotypes (HR=2.49; 95%CI: 1.06–5.85). No significant associations were observed for disease-free survival in AML patients.
By reduced DRC, this combined genotype may result in greater susceptibility to treatment effects decreasing overall survival. These findings could in the future help in selecting treatment strategies for patients with normal cytogenetics.
To date, little is known about risk factors for the development of chronic myeloid leukemia (CML). Obesity, measured as body mass index (BMI), has been identified as a possible risk factor for several solid tumors as well as some adult hematopoietic malignancies. This case-control study (N = 253 cases & 270 controls) conducted at the University of Texas MD Anderson Cancer Center investigated the role of obesity and adulthood weight gain in CML risk. Cases and controls were similar with respect to smoking, alcohol consumption, occupational solvent and ionizing radiation exposure. Cases were significantly more likely to have a history of occupational exposure to agricultural chemicals (11% cases vs. 3% controls, p=0.001). Cases were more likely to be obese during adulthood compared to controls at age 25 (OR=4.29;95%CI:1.63–11.3); at 40 (OR=5.12;95%CI:1.92–13.6) and at diagnosis (OR=3.09;95%CI:1.56–6.13). Obesity at all ages was found to be an independent risk factor, with a significant dose-response effect. Among participants ≥45 years, cases gained significantly more weight each year between ages 25–40 compared to controls (0.78 kg/yr vs. 0.44 kg/yr, P < 0.001) with the association strongest among those who gained >1kg/year between 25 and 40 years of age (OR=3.63;CI:1.46–9.04). Our results suggest that obesity and adulthood weight gain play important roles in CML risk. Several plausible biological mechanisms have been proposed and warrant further investigation. In the future, cancer prevention interventions aimed at reducing the incidence of CML could be developed.
Obesity; Weight Gain; CML Risk
Although the pathogenesis of Hodgkin disease (HD) remains unknown, the results of epidemiologic studies suggest that heritable factors are important in terms of susceptibility. Polymorphisms in DNA repair genes may contribute to individual susceptibility for development of different cancers. However, to the authors’ knowledge, few studies to date have investigated the role of such polymorphisms as risk factors for development of HD.
The authors evaluated the relation between polymorphisms in 3 nucleotide excision repair pathway genes (XPD [Lys751Gln], XPC [Lys939Gln], and XPG [Asp1104His]), the base excision repair XRCC1 (Arg399Gln), and double-strand break repair XRCC3 (Thr241Met) in a population of 200 HD cases and 220 matched controls. Variants were investigated independently and in combination; odd ratios (OR) were calculated.
A positive association was found for XRCC1 gene polymorphism Arg399Gln (OR, 1.77; 95% confidence interval [95% CI], 1.16−2.71) and risk of HD. The combined analysis demonstrated that XRCC1/XRCC3 and XRCC1/XPC polymorphisms were associated with a significant increase in HD risk. XRCC1 Arg/Arg and XRCC3 Thr/Met genotypes combined were associated with an OR of 2.38 (95% CI, 1.24−4.55). The XRCC1 Arg/Gln and XRCC3 Thr/Thr, Thr/Met, and Met/Met genotypes had ORs of 1.88 (95% CI, 1.02−4.10), 1.97 (95% CI, 1.05−3.73), and 4.13 (95% CI, 1.50−11.33), respectively. XRCC1 Gln/Gln and XRCC3 Thr/Thr variant led to a significant increase in risk, with ORs of 3.00 (95% CI, 1.15−7.80). Similarly, XRCC1 Arg/Gln together with XPC Lys/Lys was found to significantly increase the risk of HD (OR, 2.14; 95% CI, 1.09−4.23).
These data suggest that genetic polymorphisms in DNA repair genes may modify the risk of HD, especially when interactions between the pathways are considered.
DNA repair; Hodgkin disease; susceptibility; genetic polymorphisms
We assessed the expression of Matrix Metalloproteinase (MMP) to E-cadherin (M/E ratio) to determine the correlation of gene expression with pathologic variables and outcome in a cohort of African American (AA) prostate cancer patients.
Tumors from formalin-fixed, paraffin embedded RP specimens were examined. Gleason scores were 6, 7, and ≥8 in 7, 16, 13 tumors respectively. Pathologic stage was organ confined (pT2) in 18 and advanced (> pT2) in 18 tumors. A colorimetric mRNA insitu hybridization ( ISH ) assay was performed using biotinylated anti-sense oligonucleotide probes for MMP 2 and 9, as well as for E-cadherin gene transcripts. Immunohistochemistry (IHC) was performed utilizing specific monoclonal antibodies to detect the above genes. Image analysis was performed to determine the intensity of both mRNA and protein expression. Two reviewers analyzed ISH gene expression independently.
The M/E expression ratio was significantly increased at the invasive edge (but not the center) of tumors of higher Gleason score (p=0.02 and 0.0008) and pathologic stage (p=0.0001 and <0.0001) when examined by both ISH and IHC. Significant variability in ISH staining interpretation was noted within and among the two study reviewers. An M/E ratio > 2.5 was associated with biochemical recurrence after radical prostatectomy in addition to tumor pathologic stage subsequent to univariate statistical analysis.
The M/E ratio characterizes an important aspect of the molecular phenotype associated with the histologic progression of prostate cancer among African American prostate cancer patients. A larger comparative study is required to determine potential racial variation and prognostic significance of gene expression.
prostate cancer; matrix metalloproteinase; E-cadherin; African American; radical prostatectomy