NAT2 and NER genetic variants and sporadic prostate cancer susceptibility in African Americans

Genetic associations of prostate cancer in China: a systematic review

OBJECTIVES

In recent years, there has been a notable increase in the incidence and mortality rates of prostate cancer (PCa) in China, highlighting it as a significant public health issue. This study aimed to investigate the genetic association of PCa in China to better inform national disease management and medical resource allocation.

METHODS

A systematic literature review was conducted using 5 English databases (Web of Science, PubMed, Embase, Cochrane, Scopus) and 1 Chinese database (CNKI) to identify articles published from database inception to October 8, 2022, which reported the genetic associations of PCa in China.

RESULTS

Of the 11,195 articles retrieved, 41 were included in the review. A total of 116 different polymorphisms (including single nucleotide polymorphisms, deletions, insertions, and repeat lengths) in 58 genes were studied in Chinese populations. Among these, 37 out of 51 polymorphisms in 28 candidate genes such as BIRC5, C2orf43, COX-2, CYR61 (IGFBP10), DNMT1, DNMT3B, EXO1, FOXP4, and 7 unmapped SNPs were found to have either a positive or negative effect on PCa risk. However, 18 variants in 5 genes remain controversial across different studies. Additionally, 23 SNPs in 16 genes were reported to be associated with disease stage, Gleason score, PSA levels, PCa risk, and clinicopathological characteristics of PCa in China.

CONCLUSION

In Chinese populations, PCa risk and clinical features may result from individual genes, gene-gene interactions, and gene-environment interactions. These findings provide important insights into the relationship between genetic susceptibility and PCa risk in Chinese men.

Variability of DNA Repair and Oxidative Stress Genes Associated with Worst Pain in Breast Cancer Survivors on Aromatase Inhibitors

Pain is a problem affecting women with breast cancer (HR+BrCa) receiving aromatase inhibitor (AI) therapy. We investigated the relationship between single-nucleotide polymorphisms (SNPs) in DNA repair and oxidative stress genes and perceived worst pain after 6 months of AI therapy. We explored 39 SNPs in genes involved in DNA repair (ERCC2, ERCC3, ERCC5, and PARP1) and oxidative stress (CAT, GPX1, SEPP1, SOD1, and SOD2) in women with HR+BrCa receiving adjuvant therapy (AI ± chemotherapy; n = 138). Pain was assessed via the Brief Pain Inventory. Hurdle regression was used to evaluate the relationship between each associated allele and (1) the probability of pain and (2) the severity of worst pain. ERCC2rs50872 and ERCC5rs11069498 were associated with the probability of pain and had a significant genetic risk score (GRS) model (p = 0.003). ERCC2rs50872, ERCC5rs11069498, ERCC5rs4771436, ERCC5rs4150360, PARP1rs3219058, and SEPP1rs230819 were associated with the severity of worst pain, with a significant GRS model (conditional mean estimate = 0.45; 95% CI = 0.29, 0.60; p < 0.001). These results suggest DNA repair and oxidative stress pathways may play a role in the probability of pain and the severity of worst pain. As healthcare delivery moves towards the model of precision healthcare, nurses may, in the future, be able to use these results to tailor patient care based on GRS.

Racial Differences in Germline Genetic Testing for Prostate Cancer: A Systematic Review

PURPOSE

Testing for pathogenic variants can aid in oncologic risk stratification and identification of targeted therapies. Despite known disparities in access to prostate cancer (PCa) care, little has been written about access to germline genetic testing (GGT) for Black men and other historically marginalized populations. This systematic review sought to delineate racial/ethnic disparities in GGT for PCa.

METHODS

This systematic review identified articles published from January 1996 through May 2021 in PubMed, Web of Science, and Embase. We included studies that reported rates of GGT in men with PCa in the United States by race/ethnicity as reflective of routine clinical care or research. A narrative synthesis was performed.

RESULTS

Of 4,309 unique records, 91 studies examining 50 unique study populations met inclusion criteria. Of these, four populations included men who received GGT through routine clinical care, accounting for 4,415 men (72.6% White and 7.2% Black). The other 46 populations included men who received GGT as part of a research study, accounting for 30,824 men (64.3% White and 21.6% Black). Of these 46 research populations, 19 used targeted methods to increase recruitment from a specific demographic.

CONCLUSION

Most studies that report GGT rates by race/ethnicity are in research settings. Many of these studies used targeted recruitment methods and subsequently have a greater proportion of Black men than clinical and US population-based studies. Other historically marginalized populations are not well represented. There remains a knowledge gap regarding the extent of racial disparities in the use of GGT, particularly in the clinical setting.

The interplay of pineal hormones and socioeconomic status leading to colorectal cancer disparity

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the United States. Despite increased screening options and state-of-art treatments offered in clinics, racial differences remain in CRC. African Americans (AAs) are disproportionately affected by the disease; the incidence and mortality are higher in AAs than Caucasian Americans (CAs). At the time of diagnosis, AAs more often present with advanced stages and aggressive CRCs, primarily accounting for the racial differences in therapeutic outcomes and mortality. The early incidence of CRC in AAs could be attributed to race-specific gene polymorphisms and lifestyle choices associated with socioeconomic status (SES). Altered melatonin-serotonin signaling, besides the established CRC risk factors (age, diet, obesity, alcoholism, and tobacco use), steered by SES, glucocorticoid, and Vitamin D status in AAs could also account for the early incidence in this racial group. This review focuses on how the lifestyle factors, diet, allelic variants, and altered expression of specific genes could lead to atypical serotonin and melatonin signaling by modulating the synthesis, secretion, and signaling of these pineal hormones in AAs and predisposing them to develop more aggressive CRC earlier than CAs. Crosstalk between gut microbiota and pineal hormones and its impact on CRC pathobiology is addressed from a race-specific perspective. Lastly, the status of melatonin-focused CRC treatments, the need to better understand the perturbed melatonin signaling, and the potential of pineal hormone-directed therapeutic interventions to reduce CRC-associated disparity are discussed.

Germline Predisposition to Prostate Cancer in Diverse Populations

There remains a paucity of data related to germline genetic alterations predisposing patients to prostate cancer. Recent data suggest that African American, Hispanic, and Asian and Pacific Islander men exhibit genetic alterations in both highly penetrant germline genes, including BRCA1/2, ATM, and CHEK2, and the mismatch repair genes associated with Lynch syndrome, as well as low-penetrant single-nucleotide polymorphisms. However, cohort sizes remain small in many studies limiting the ability to determine clinical significance, appropriate risk stratification, and treatment implications in these diverse populations.

Polymorphisms in ERCC2 and ERCC5 and Risk of Prostate Cancer: A Meta-Analysis and Systematic Review

Background and Objective: Excision repair cross complementing (ERCC) group genes play important roles in the nucleotide excision repair (NER) way, which can effectively remove bulky lesions and reduce UV-caused DNA damage by environmental chemicals. Polymorphisms in ERCCs were thought to be related to prostate cancer (PCa) risk. However, it has been unclear whether this relationship is consistent. This study aimed to obtain the overall profile regarding the associations between ERCCs polymorphisms and PCa risk. Materials and Methods: We identified relevant studies by a systematic search of PubMed, Medline, Embase, Google Scholar databases, Web of Science and Wanfang databases up to April 8, 2018. Odds ratios (ORs) with 95% confidential intervals (95%CIs) were conducted to evaluate the associations. All the statistical analyses were conducted basing on STATA 12.0 software. Results: Finally, a total of 29 previous studies published in 17 publications were included for four polymorphisms in two DNA repair genes (ERCC2-rs1799793, ERCC2-rs238406, ERCC2-rs13181 and ERCC5-rs17655). Overall, we observed no significant connection between these four polymorphisms and PCa risk. However, after stratifying the studies by ethnicity, ERCC2-rs1799793 polymorphism was associated with an increased risk of PCa in Asian patients and the relationship was subsequently validated with the allelic model, the homozygous model and the recessive model when extracting the data of Asian patients for specific analyses (B vs. A: OR = 1.537, 95%CI: 1.240-1.906, PA< 0.001; BB vs. AA: OR = 2.089, 95%CI: 1.388-3.145, PA< 0.001 and BB vs. BA + AA: OR = 1.929, 95%CI: 1.313-2.835, PA= 0.020). Furthermore, subgroup analyses were also conducted by Hardy-Weinberg Equilibrium (HWE) and source of control, negative results were identified for ERCC2-rs238406, ERCC2-rs13181 and ERCC5-rs17655 polymorphisms (PA> 0.050). Conclusion: To sum up, our work demonstrated that ERCC2-rs1799793 polymorphism is positively associated with PCa risk in Asian population. Further larger-scale studies with subjects of the same ethnicity and biological characteristics are required to verify these findings.

XPG rs17655 G>C polymorphism associated with cancer risk: evidence from 60 studies

Xeroderma pigmentosum group G (XPG), a key component in nucleotide excision repair pathway, functions to cut DNA lesions during DNA repair. Genetic variations that alter DNA repair gene expression or function may decrease DNA repair ability and impair genome integrity, thereby predisposing to cancer. The association between XPG rs17655 G>C polymorphism and cancer risk has been investigated extensively, but the results remain contradictory. To get a more accurate conclusion, we performed a comprehensive meta-analysis of 60 case-control studies, involving 27,098 cancer cases and 30,535 healthy controls. Crude odds ratios (ORs) and 95% confidence interval (CIs) were calculated to determine the association of interest. Pooled analysis indicated that the XPG rs17655 G>C polymorphism increased the risk of overall cancer (CC vs. GG: OR=1.10, 95% CI=1.00-1.20; CG vs. GG: OR=1.06, 95% CI=1.02-1.11; CG+CC vs. GG: OR=1.07, 95% CI=1.02-1.12; C vs. G: OR=1.05, 95% CI=1.01-1.09). Stratification analysis by cancer type further showed that this polymorphism was associated with increased risk of gastric cancer and colorectal cancer. This meta-analysis indicated that the XPG gene rs17655 G>C polymorphism was associated with increased overall cancer risk, especially the risk of gastric cancer and colorectal cancer. Further validation experiments are needed to strength our conclusion.

XPG gene polymorphisms and cancer susceptibility: evidence from 47 studies

Xeroderma pigmentosum group G (XPG) is a single-strand-specific DNA endonuclease that functions in the nucleotide excision repair pathway. Genetic variations in XPG gene can alter the DNA repair capacity of this enzyme. We evaluated the associations between six single nucleotide polymorphisms (SNPs) in XPG (rs1047768 T>C, rs2296147 T>C, rs2227869 G>C, rs2094258 C>T, rs751402 C>T, and rs873601 G>A) and cancer risk. Forty-seven studies were identified in searches of the PubMed, Scopus, Web of Science, China National Knowledge Infrastructure, and WanFang databases. Crude odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a fixed or random effects model. We found that rs873601 G>A was associated with an increased overall cancer risk (AA vs. GG: OR = 1.14, 95% CI = 1.06–1.24; GA/AA vs. GG: OR = 1.08, 95% CI = 1.02–1.15; A vs. G: OR = 1.06, 95% CI = 1.02–1.10). In a stratified analysis, rs1047768 T>C was associated with an increased risk of lung cancer, rs2227869 G>C was associated with a decreased risk of cancer in population-based studies, and rs751402 C>T and rs873601 G>A were associated with the risk of gastric cancer. Our data indicate that rs873601 G>A is associated with cancer susceptibility.

Polymorphisms in nucleotide excision repair genes and risk of primary prostate cancer in Chinese Han populations

Genetic variants of nucleotide excision repair (NER) genes have been extensively investigated for their roles in the development of prostate cancer (PCa); however, the published results have been inconsistent. In a hospital-based case-control study of 1,004 PCa cases and 1,055 cancer-free controls, we genotyped eight potentially functional single nucleotide polymorphisms (SNPs) of NER genes (i.e., XPC, rs2228001 T>G and rs1870134 G>C; XPD, rs13181 T>G and rs238406 G>T; XPG, rs1047768 T>C, rs751402 C>T, and rs17655 G>C; and XPF, rs2276464 G>C) and assessed their associations with risk of PCa by using logistic regression analysis. Among these eight SNPs investigated, only XPC rs1870134 CG/CC variant genotypes were associated with a decreased risk of prostate cancer under a dominant genetic model (adjusted odds ratio [OR] = 0.77, 95% confidence interval [CI] = 0.64-1.91, P = 0.003). Phenotype-genotype analysis also suggested that the XPC rs1870134 CG/CC variant genotypes were associated with significantly decreased expression levels of XPC mRNA in a mix population of different ethnicities. These findings suggested that XPC SNPs may contribute to risk of PCa in Eastern Chinese men.

Meta-analysis reveals no significant association between ERCC6 polymorphisms and bladder cancer risk

BACKGROUND

Numerous studies have been conducted to evaluate the association between excision repair cross-complementing group 6 (ERCC6) gene polymorphisms and bladder cancer risk, but their findings have been inconsistent. Here we performed a meta-analysis to attempt to clarify this association.

METHODS

Studies were retrieved from the PubMed and China National Knowledge Infrastructure databases up to October 1, 2015, with strict selection and exclusion criteria. A total of 5,032 samples, comprising samples from 2,475 bladder cancer patients and 2,557 controls from 5 studies, were included in the meta-analysis. The odds ratio (OR) with 95% confidence interval (CI) was used to evaluate the strength of the associations.

RESULTS

Regarding the Met1097Val polymorphism, no significant association with bladder cancer risk was found in any of the genetic models evaluated (Val vs. Met: OR = 1.10, 95% CI, 0.97-1.25; Val/Val vs. Met/Met: OR = 1.23, 95% CI, 0.86-1.75; Val/Val + Val/Met vs. Met/Met: OR = 1.12, 95% CI, 0.96-1.30; Val/Val vs. Met/Met + Val/Met: OR = 0.81, 95% CI, 0.57-1.14). Similarly, as regards the Arg1230Pro polymorphism, we also found no positive results.

CONCLUSIONS

According to the results of our meta-analysis, there is no evidence of a link between the ERCC6 gene polymorphisms and bladder cancer risk. Well-designed further studies, with larger sample sizes and adjustment for confounders such as smoking status, are needed to confirm these conclusions.

Polymorphisms in DNA repair and oxidative stress genes associated with pre-treatment cognitive function in breast cancer survivors: an exploratory study

PURPOSE

The purpose of this exploratory candidate gene association study was to examine relationships between polymorphisms in oxidative stress and DNA repair genes and pre-adjuvant therapy cognitive function (CF) in postmenopausal women diagnosed with early stage-breast cancer.

METHODS

Using a neuropsychological test battery, CF was assessed in 138 women diagnosed with breast cancer prior to initiation of adjuvant therapy and 81 age- and education-matched controls and summarized across eight composites. Participants were genotyped for 39 functional or tagging single nucleotide polymorphisms (SNPs) of select oxidative stress (CAT, GPX1, SEPP1, SOD1, and SOD2) and DNA repair (ERCC2, ERCC3, ERCC5, and PARP1) genes. Multiple linear regression was used to determine if the presence or absence of one or more minor alleles account for variability in CF composite scores. Based on regression findings from the analysis of individual SNPs, weighted multi-gene, multi-polymorphism genetic risk scores (GRSs) were calculated to evaluate the collective effect of possession of multiple protective and/or risk alleles.

RESULTS

Each CF composite was significantly (p < 0.05) associated with one or more oxidative stress and DNA repair gene polymorphisms evaluated either by SNP main effects and/or SNP-by-prescribed breast cancer treatment group interactions. Each computed GRS was found to be significantly (p < 0.001) related to its corresponding CF composite. All associations were positive suggesting that as overall genetic protection increases, CF composite score increases (indicating better performance).

CONCLUSIONS

These findings suggest that genetic variation in the oxidative stress and DNA repair pathways may play an important role in pre-adjuvant therapy CF in breast cancer survivors.

Incidence of prostate and urological cancers in England by ethnic group, 2001-2007: a descriptive study

Background

The aetiology of urological cancers is poorly understood and variations in incidence by ethnic group may provide insights into the relative importance of genetic and environmental risk factors. Our objective was to compare the incidence of four urological cancers (kidney, bladder, prostate and testicular) among six ‘non-White’ ethnic groups in England (Indian, Pakistani, Bangladeshi, Black African, Black Caribbean and Chinese) to each other and to Whites.

Methods

We obtained Information on ethnicity for all urological cancer registrations from 2001 to 2007 (n = 329,524) by linkage to the Hospital Episodes Statistics database. We calculated incidence rate ratios adjusted for age, sex and income, comparing the six ethnic groups (and combined ‘South Asian’ and ‘Black’ groups) to Whites and to each other.

Results

There were significant differences in the incidence of all four cancers between the ethnic groups (all p < 0.001). In general, ‘non-White’ groups had a lower incidence of urological cancers compared to Whites, except prostate cancer, which displayed a higher incidence in Blacks. (IRR 2.55) There was strong evidence of differences in risk between Indians, Pakistanis and Bangladeshis for kidney, bladder and prostate cancer (p < 0.001), and between Black Africans and Black Caribbeans for all four cancers (p < 0.001).

Conclusions

The risk of urological cancers in England varies greatly by ethnicity, including within groups that have traditionally been analysed together (South Asians and Blacks). In general, these differences are not readily explained by known risk factors, although the very high incidence of prostate cancer in both black Africans and Caribbeans suggests increased genetic susceptibility. g.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1771-2) contains supplementary material, which is available to authorized users.

Role of DNA repair-related gene polymorphisms in susceptibility to risk of prostate cancer

AIM

We assessed the association between genetic variants of XPG, XPA, XPD, CSB, XPC and CCNH in the nucleotide excision repair (NER) pathway and risk of prostate cancer.

METHODS

We genotyped the XPG, XPA, XPD, CSB, XPC and CCNH polymorphisms by a 384-well plate format on the MassARRAY® platform. Multivariate logistical regression analysis was used to assess the associations between the six gene polymorphisms and risk of prostate cancer.

RESULTS

Individuals carrying the XPG rs229614 TT (OR=2.01, 95%CI=1.35-3.27) genotype and T allele (OR=1.73, 95%CI=1.37-2.57) were moderately significantly associated with a higher risk of prostate cancer. Subjects with XPD rs13181 G allele had a marginally increased risk of prostate cancer, with adjusted OR(95%CI) of 1.53 (1.04-2.37). Moreover, individuals carrying with CSB rs2228526 GG genotype (OR=2.05, 95% CI=1.23-3.52) and G allele (OR=1.56, 95%CI=1.17-2.05) were associated with a higher increased risk of prostate cancer. The combination genotype of XPG rs2296147 T and CSB rs2228526 G allele had accumulative effect on the risk of this cancer, with an OR (95% CI) of 2.23(1.37-3.59).

CONCLUSIONS

Our study indicates that XPG rs2296147 and CSB rs2228526 polymorphisms are significantly associated with increased risk of prostate cancer, and that combination of XPG rs2296147 T allele and CSB rs2228526 G allele is strongly associated with an increased risk.

The DNA repair gene ERCC6 rs1917799 polymorphism is associated with gastric cancer risk in Chinese

OBJECTIVE

Excision repair cross-complementing group 6 (ERCC6) is a major component of the nucleotide excision repair pathway that plays an important role in maintaining genomic stability and integrity. Several recent studies suggested a link of ERCC6 polymorphisms with susceptibility to various cancers. However, the relation of ERCC6 polymorphism with gastric cancer (GC) risk remains elusive. In this sex- and age- matched case-control study including 402 GC cases and 804 cancer-free controls, we aimed to investigate the association between a potentially functional polymorphism (rs1917799 T>G) in the ERCC6 regulatory region and GC risk.

METHODS

The genotypes of rs1917799 were determined by Sequenom MassARRAY platform and the status of Helicobacter pylori infection was detected by enzyme-linked immunosorbent assay. Odd ratios (ORs) and 95% confidential interval (CI) were calculated by logistic regression analysis.

RESULTS

Compared with the common TT genotype, the ERCC6 rs1917799 GG genotype was associated with increased GC risk (adjusted OR=1.46, 95%CI: 1.03-2.08, P=0.035). When compared with (GT+TT) genotypes, the GG genotype also demonstrated a statistical association with increased GC risk (adjusted OR=1.38, 95%CI: 1.01-1.89, P=0.044). This was also observed for the male subpopulation (GG vs. TT: adjusted OR=1.71, 95%CI: 1.12-2.62, P=0.013; G allele vs. T allele: adjusted OR=1.32, 95%CI: 1.07-1.62, P=0.009). Genetic effects on increased GC risk tended to be enhanced by H. pylori infection, smoking and drinking, but their interaction effects on GC risk did not reach statistical significance.

CONCLUSIONS

ERCC6 rs1917799 GG genotype might be associated with increased GC risk in Chinese, especially in males.

Variation in N-acetyltransferase 2 (NAT2), smoking and risk of prostate cancer in the Slovak population

N-acetyltransferase 2 (NAT2) is an enzyme involved in the biotransformation of xenobiotics, mainly aromatic and heterocyclic amines and hydrazines, all of which represent an important class of carcinogens found in tobacco smoke. Polymorphism in NAT2 gene is reported to be associated with susceptibility to various types of cancer. This study investigated the relationship between the NAT2 polymorphism and the risk of prostate cancer with reference to the link between cigarette smoking and the xenobiotic-metabolizing enzyme NAT2. Overall, 281 cases and 395 controls from Slovakia were studied using polymerase chain reaction-restriction fragment length polymorphism assay. We found no statistically significant association between NAT2 genotypes and prostate cancer risk (slow acetylation vs. rapid acetylation: OR 1.13; 95 % CI 0.83-1.55). We report here a statistically significant correlation between the NAT2*5C/NAT2*6A slow acetylator genotype and the risk for developing prostate cancer (OR 2.91; 95 % CI 1.43-5.94; p = 0.003) when compared with the rapid phenotype. Smokers with NAT2 rapid phenotype had a five percent (5 %) reduced risk of prostate cancer compared with non-smokers carrying the rapid acetylator genotype. The association was reversed among smokers and non-smokers with NAT2 slow phenotype. On the basis of the foregoing, we conclude that the NAT2 phenotypes whether alone or in association with smoking do not correlate with susceptibility to prostate cancer within the Slovak population.

Association between the XPG Asp1104His and XPF Arg415Gln polymorphisms and risk of cancer: a meta-analysis

BACKGROUND

The XPG (xeroderma pigmentosum type G) Asp1104His and XPF (xeroderma pigmentosum type F) Arg415Gln polymorphisms had been implicated in cancer susceptibility. The previous published data on the association between XPG Asp1104His and XPF Arg415Gln polymorphisms and cancer risk remained controversial.

METHODOLOGY/PRINCIPAL FINDINGS

To derive a more precise estimation of the association between the XPG Asp1104His and XPF Arg415Gln polymorphisms and overall cancer risk, we performed a meta-analysis to investigate the association between cancer susceptibility and XPG Asp1104His (32,162 cases and 39,858 controls from 66 studies) and XPF Arg415Gln polymorphisms (17,864 cases and 20,578 controls from 32 studies) in different inheritance models. We used odds ratios with 95% confidence intervals to assess the strength of the association. Overall, significantly elevated cancer risk was found when all studies were pooled into the meta-analysis of XPG Asp1104His (dominant model: OR = 1.05, 95% CI = 1.00-1.10; Asp/His vs. Asp/Asp: OR = 1.06, 95% CI = 1.01-1.11). In the further stratified and sensitivity analyses, significantly decreased lung cancer risk was found for XPF Arg415Gln (dominant model: OR = 0.82, 95% CI = 0.71-0.96; Arg/Gln versus Arg/Arg: OR = 0.83, 95% CI = 0.71-0.97; additive model: OR = 0.83, 95% CI = 0.72-0.95) and significantly increased other cancer risk was found among hospital-based studies for XPG Asp1104His (dominant model: OR = 1.23, 95% CI = 1.02-1.49).

CONCLUSIONS/SIGNIFICANCE

In summary, this meta-analysis suggests that XPF Arg415Gln polymorphism may be associated with decreased lung cancer risk and XPG Asp1104His may be a low-penetrant risk factor in some cancers development. And larger scale primary studies are required to further evaluate the interaction of XPG Asp1104His and XPF Arg415Gln polymorphisms and cancer risk in specific populations.

N-acetyltransferase-2 gene polymorphisms and prostate cancer susceptibility in Latin American patients

We investigated the role of N-acetyltransferases (NAT) in prostate cancer (PCa) susceptibility. NAT are polymorphic in the population and metabolize important carcinogenic products directly involved in the tumor initiation process. This prospective case-control study utilized the polymerase chain reaction-based restriction fragment length polymorphism method and comprised a cohort of consecutive 478 individuals: 126 men with prostate cancer; 101 men with benign prostatic hyperplasia (BPH); and a control health population of 177 female and 74 male blood donors from the same region. NAT2 slow or fast acetylators genotypes were determined by the combination of four variant alleles. Lifetime occupational history, dietary patterns, cigarette smoking and other anamnestic data were obtained by interviews. We were not able to find any correlation among smoking, dietary patterns, parameters of tumor aggressiveness or patient outcome and any NAT2 genotypes or phenotypes considered in separate or in different combinations. However, there was an association between NAT2T481C (OR=0.47; 95% CI=0.26-0.84; P=0.01) and NAT2A803G (OR=0.57; 95% CI=0.33-0.97; P=0.04) polymorphisms and PCa protection. Conversely, the presence of NAT2G857A genotype increased the risk of PCa more than 3 times (OR=3.57; 95% CI=1.39-9.15; P=0.005). Slow acetylator NAT2*7A and NAT2*6B genotypes occurred in 10.31% of PCa but in none of BPH patients (P=0.0007). The control health population confirmed the results and allowed the exclusion of possible biases caused by gender influence on genotype inheritance and by the inclusion of not diagnosed prostate diseases patients among the control individuals. We suggest that the investigation of germline polymorphisms of NAT2 gene may be useful in the assessment of Latin American patients at risk of BPH and PCa.

Deficiency of DNA repair nuclease ERCC1-XPF promotes prostate cancer progression in a tissue recombination model

BACKGROUND

The excision repair cross complementing (ERCC1) gene product plays a vital role in the nucleotide excision repair (NER) and DNA interstrand crosslink repair pathways, which protect the genome from mutations and chromosomal aberrations, respectively. Genetic deletion of Ercc1 in the mouse causes dramatically accelerated aging. We examined the effect of Ercc1 deletion in the development of prostate cancer in a prostate recapitulation model as Ercc1 deficient mice die within four weeks of birth.

METHODS

Prostate tissues from Ercc1(-/-) mice or wild-type littermates were combined with embryonic rat urogenital mesenchyme and grown as renal grafts for a total of 8, 16, and 24 weeks before histological, expression and proliferative evaluation.

RESULTS

Invasive adenocarcinoma was observed in Ercc1(-/-) tissue recombinants but not wild-type as early as 8 weeks post-grafting. PIN-like lesions in Ercc1(-/-) tissue recombinants had more cytologic and architectural atypia than wild-type (P = 0.02, P = 0.0065, and P = 0.0003 at the 8, 16, and 24 weeks, respectively), as well as more proliferative cells (P = 0.022 and P = 0.033 at 8 and 16 weeks, respectively). With serial grafting, Ercc1(-/-) tissue recombinants progressed to a more severe histopathological phenotype more rapidly than wild-type (P = 0.011).

CONCLUSIONS

Results show that ERCC1 and by implication the NER and/or interstrand crosslink repair mechanisms protect against prostate carcinogenesis and mutations or polymorphisms affecting these DNA repair pathways may predispose prostate epithelial cells to transformation.

Association between the ERCC5 Asp1104His polymorphism and cancer risk: a meta-analysis

BACKGROUND

Excision repair cross complementing group 5 (ERCC5 or XPG) plays an important role in regulating DNA excision repair, removal of bulky lesions caused by environmental chemicals or UV light. Mutations in this gene cause a rare autosomal recessive syndrome, and its functional single nucleotide polymorphisms (SNPs) may alter DNA repair capacity phenotype and cancer risk. However, a series of epidemiological studies on the association between the ERCC5 Asp1104His polymorphism (rs17655, G>C) and cancer susceptibility generated conflicting results.

METHODOLOGY/PRINCIPAL FINDINGS

To derive a more precise estimation of the association between the ERCC5 Asp1104His polymorphism and overall cancer risk, we performed a meta-analysis of 44 published case-control studies, in which a total of 23,490 cases and 27,168 controls were included. To provide additional biological plausibility, we also assessed the genotype-gene expression correlation from the HapMap phase II release 23 data with 270 individuals from 4 ethnic populations. When all studies were pooled, we found no statistical evidence for a significantly increased cancer risk in the recessive genetic models (His/His vs. Asp/Asp: OR = 0.99, 95% CI: 0.92-1.06, P = 0.242 for heterogeneity or His/His vs. Asp/His + Asp/Asp: OR = 0.98, 95% CI: 0.93-1.03, P = 0.260 for heterogeneity), nor in further stratified analyses by cancer type, ethnicity, source of controls and sample size. In the genotype-phenotype correlation analysis from 270 individuals, we consistently found no significant correlation of the Asp1104His polymorphism with ERCC5 mRNA expression.

CONCLUSIONS/SIGNIFICANCE

This meta-analysis suggests that it is unlikely that the ERCC5 Asp1104His polymorphism may contribute to individual susceptibility to cancer risk.

Association between XPF polymorphisms and cancer risk: a meta-analysis

BACKGROUND

Xeroderma pigmentosum complementation group F (XPF or ERCC4) plays a key role in DNA repair that protects against genetic instability and carcinogenesis. A series of epidemiological studies have examined associations between XPF polymorphisms and cancer risk, but the findings remain inconclusive.

METHODOLOGY/PRINCIPAL FINDINGS

In this meta-analysis of 47,639 cancer cases and 51,915 controls, by searching three electronic databases (i.e., MEDLINE, EMBASE and CNKI), we summarized 43 case-control studies from 29 publications on four commonly studied polymorphisms of XPF (i.e., rs1800067, rs1799801, rs2020955 and rs744154), and we did not find statistical evidence of any significant association with overall cancer risk. However, in stratification analyses, we found a significant association of XPF-rs1799801 with a reduced cancer risk in Caucasian populations (4,845 cases and 5,556 controls; recessive model: OR=0.87, 95% CI=0.76-1.00, P=0.049, P=0.723 for heterogeneity test, I(2) =0). Further genotype-phenotype correlation analysis showed that the homozygous variant CC genotype carriers had higher XPF expression levels than that of the TT genotype carriers (Student's t test for a recessive model: P=0.046). No publication bias was found by using the funnel plot and Egger's test.

CONCLUSION

This meta-analysis suggests a lack of statistical evidence for the association between the four XPF SNPs and overall risk of cancers. However, XPF-rs1799801 may be associated with cancer risk in Caucasian populations, which needs to be further validated in single large, well-designed prospective studies.

DNA repair genes polymorphism (XPG and XRCC1) and association of prostate cancer in a north Indian population

Prostate cancer is the most commonly diagnosed cancer in men worldwide and is the second leading cause of cancer related mortality. Genetic background may account for the difference in susceptibility of individuals to different diseases and the relationship between genetic polymorphism and some diseases has been extensively studied. There are several common polymorphisms in genes encoding DNA repair enzymes, some of these polymorphisms are reported to result in subtle structural alterations of the repair enzyme and modulation of the repair capacity. The aim of the present study was to analyze the effect of XPG Asp 1104His and XRCC1 Arg309Gln polymorphisms on risk of prostate cancer in north Indian population. Statistically significant increased risk of prostate cancer was observed on individuals that posses His/His genotype of XPG (OR 2.53, 95% CI 0.99-6.56, P = 0.031). In this study 150 prostate cancer diagnosed patients, 150 healthy controls and 150 BPH (benign prostate hyper plasia) were recruited from north Indian population. Moreover, individuals that carried the Gln/Gln genotype of XRCC1 also showed statistically increased risk of prostate cancer (OR 2.06, 95% CI 1.07-4.00, P = 0.033). The Asp/Asp of XPG and Gln/Gln of XRCC1 in combination showed statistically increased risk of prostate cancer in cases (OR 3.29, 95% CI 1.09-10.16, P = 0.032).

Mechanisms of prostate cancer initiation and progression

Prostate cancer is a major health problem as it continues to be the most frequently diagnosed cancer in men in the Western world. While improved early detection significantly decreased mortality, prostate cancer still remains the second leading cause of cancer-related death in Western men. Understanding the mechanisms of prostate cancer initiation and progression should have a significant impact on development of novel therapeutic approaches that can help to combat this disease. The recent explosion of novel high-throughput genetic technologies together with studies in animal models and human tissues allowed a comprehensive analysis and functional validation of the molecular changes. This chapter will summarize and discuss recently identified critical genetic and epigenetic changes that drive prostate cancer initiation and progression. These discoveries should help concentrate the efforts of drug development on key pathways and molecules, and finally translate the knowledge that is gained from mechanistic studies into effective treatments.

No association between variant N-acetyltransferase genes, cigarette smoking and Prostate Cancer susceptibility among men of African descent

OBJECTIVE: We evaluated the individual and combination effects of NAT1, NAT2 and tobacco smoking in a case-control study of 219 incident prostate cancer (PCa) cases and 555 disease-free men. METHODS: Allelic discriminations for 15 NAT1 and NAT2 loci were detected in germ-line DNA samples using TaqMan polymerase chain reaction (PCR) assays. Single gene, gene-gene and gene-smoking interactions were analyzed using logistic regression models and multi-factor dimensionality reduction (MDR) adjusted for age and subpopulation stratification. MDR involves a rigorous algorithm that has ample statistical power to assess and visualize gene-gene and gene-environment interactions using relatively small samples sizes (i.e., 200 cases and 200 controls). RESULTS: Despite the relatively high prevalence of NAT1*10/*10 (40.1%), NAT2 slow (30.6%), and NAT2 very slow acetylator genotypes (10.1%) among our study participants, these putative risk factors did not individually or jointly increase PCa risk among all subjects or a subset analysis restricted to tobacco smokers. CONCLUSION: Our data do not support the use of N-acetyltransferase genetic susceptibilities as PCa risk factors among men of African descent; however, subsequent studies in larger sample populations are needed to confirm this finding.

Cis-acting genetic variation at an E2F1/YY1 response site and putative p53 site is associated with altered allele-specific expression of ERCC5 (XPG) transcript in normal human bronchial epithelium

ERCC5 (XPG) is a key component of the nucleotide excision DNA repair pathway. In two recent case-control studies, we determined that ERCC5 transcript expression pattern in grossly normal human bronchial epithelial cells (NBEC) was different in individuals diagnosed with lung cancer compared with non-lung cancer controls. In this study, we tested the hypothesis that variation at cis-acting sites contributed to observed variation in ERCC5 transcript expression in NBEC. Allele-specific expression (ASE) was measured at transcribed polymorphic site rs1047768 in exon 2 of ERCC5 in NBEC complementary DNA (cDNA) of 22 individuals using allele-specific competitive polymerase chain reaction. ASE at rs1047768 was then assessed for association with allelotype at polymorphic sites rs751402 (E2F1 and YY1 recognition and response site) and rs2296147 (putative P53 recognition site) in the proximal promoter and 5' untranslated region, respectively, of ERCC5. Interindividual variation in recombination between rs751402, rs2296147 and rs1047768 in poly-heterozygotes was controlled for by allele-specific sequencing. Measured rs1047768 T:C allelic ratio was (i) significantly higher in NBEC cDNA compared with genomic DNA controls (P < 0.001) among samples heterozygous at both rs751402 and rs2296147; (ii) less high (P = 0.02) for samples homozygous at rs751402 but heterozygous at rs2296147 and (iii) not significantly different (P = 0.18) for doubly homozygous individuals. Here, we demonstrate that rs751402 A allele and rs2296147 T allele are associated with higher ASE of ERCC5 T allele transcript at rs1047768 in NBEC.

Review of studies on metabolic genes and cancer in populations of African descent

Genetic polymorphisms described for a number of enzymes involved in the metabolism of tobacco carcinogens and alcohol have been linked to increase cancer risk. Racial disparities in cancer between whites and populations of African descent are well documented. In addition to differences in access to health care, both environment and genetic factors and their interaction may contribute to the increased cancer risk in minority populations. We reviewed the literature to identify case-control studies that included subjects of African descent. Meta-analyses investigating the association of genetic polymorphisms in tobacco metabolic genes and cancer were performed. Although several genes and cancers have been studied, only one or two studies per gene for each cancer site have been published, with the exception of breast (CYP1A1 and CYP1B1), lung (GSTM1, CYP1A1, and NQO1), and prostate (CYP3A4 A293G and CYP17). Marginal statistically significant associations were observed for CYP3A4 A293G and CYP17 5'UTR polymorphisms and prostate cancer. Our findings support the need for additional genetic association studies of breast, prostate, and lung cancers that include a larger number of minority participants. Because incidence and mortality rates for these cancers rank highest among populations of African descent, concentrated research in these areas are warranted.

No association between variant DNA repair genes and prostate cancer risk among men of African descent

BACKGROUND

Recent reports hypothesize that multiple variant DNA repair gene interactions influence cancer susceptibility. However, studies identifying high-risk cancer-related genes use single gene approaches that lack the statistical rigor to model higher order interactions.

METHODS

To address this issue, we systematically evaluated individual and joint modifying effects of commonly studied polymorphic base and nucleotide excision repair genes relative to prostate cancer (PCA) risk using conventional logistic regression models and multifactor dimensionality reduction (MDR). We hypothesized that inheriting two or more compromised DNA repair loci may increase PCA risk due to altered gene product function. Six genetic alterations were evaluated using germ-line DNA samples from 208 PCA cases and 665 disease-free controls via TaqMan polymerase chain reaction.

RESULTS

With the exception of XPD 312, no association existed between individual DNA repair single-nucleotide polymorphisms (SNPs) and PCA. Individuals with the XPD 312 Asn/Asn genotype had an 8.6-fold increase in risk (OR = 8.59; 95% CI = 1.81-40.66). We did not observe any significant single gene or gene-gene interactions based on MDR modeling.

CONCLUSIONS

Our findings emphasize the importance of utilizing a combination of traditional and advanced statistical tools to identify and validate single gene and multilocus interactions in relation to cancer susceptibility.

Genetic variation in DNA repair genes and prostate cancer risk: results from a population-based study

OBJECTIVE

DNA repair pathways are crucial to prevent accumulation of DNA damage and maintain genomic stability. Alterations of this pathway have been reported in many cancers. An increase in oxidative DNA damage or decrease in DNA repair capacity with aging or due to germline genetic variation may affect prostate cancer risk.

METHODS

Pooled data from two population-based studies (1,457 cases and 1,351 controls) were analyzed to examine associations between 28 single-nucleotide polymorphisms (SNPs) in nine DNA repair genes (APEX1, BRCA2, ERCC2, ERCC4, MGMT, MUTYH, OGG1, XPC, and XRCC1) and prostate cancer risk. We also explored whether associations varied by smoking, by family history or clinical features of prostate cancer.

RESULTS

There were no associations between these SNPs and overall risk of prostate cancer. Risks by genotype also did not vary by smoking or by family history of prostate cancer. Although two SNPs in BRCA2 (rs144848, rs1801406) and two SNPs in ERCC2 (rs1799793, rs13181) showed stronger associations with high Gleason score or advanced-stage tumors when comparing homozygous men carrying the minor versus major allele, results were not statistically significantly different between clinically aggressive and non-aggressive tumors.

CONCLUSION

Overall, this study found no associations between prostate cancer and the SNPs in DNA repair genes. Given the complexity of this pathway and its crucial role in maintenance of genomic stability, a pathway-based analysis of all 150 genes in DNA repair pathways, as well as exploration of gene-environment interactions may be warranted.

A meta-analysis of the NAT1 and NAT2 polymorphisms and prostate cancer: a huge review

Studies revealing conflicting results on the role of NAT1 or NAT2 phenotypes on prostate cancer risk led us to perform a meta-analysis to investigate the association of these polymorphisms and prostate cancer risk. The meta-analysis included six studies with NAT1 genotyping (610 prostate cancer cases and 713 controls), and 10 studies with NAT2 genotyping (1,253 cases and 1,722 controls). The fixed effects odds ratio was 0.96 [95% confidence interval (95% CI): 0.75, 1.21; I(2) = 32.9%, P for heterogeneity = 0.189] for the NAT1 genotype, and the random effects odds ratio was 1.10 (95% CI: 0.87, 1.39; I(2) = 49.1%, P for heterogeneity = 0.039) for the NAT2 genotype. For NAT2 polymorphism, a statistically significant association between NAT2 polymorphism and prostate cancer appeared in Asians, but not in Caucasians. In conclusion, the NAT1 or NAT2 phenotypes detoxify carcinogens and their reactive intermediates are unlikely to be the cause of PCa development.

Evaluation of a candidate breast cancer associated SNP in ERCC4 as a risk modifier in BRCA1 and BRCA2 mutation carriers. Results from the Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA)

Background:

In this study we aimed to evaluate the role of a SNP in intron 1 of the ERCC4 gene (rs744154), previously reported to be associated with a reduced risk of breast cancer in the general population, as a breast cancer risk modifier in BRCA1 and BRCA2 mutation carriers.

Methods:

We have genotyped rs744154 in 9408 BRCA1 and 5632 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and assessed its association with breast cancer risk using a retrospective weighted cohort approach.

Results:

We found no evidence of association with breast cancer risk for BRCA1 (per-allele HR: 0.98, 95% CI: 0.93–1.04, P=0.5) or BRCA2 (per-allele HR: 0.97, 95% CI: 0.89–1.06, P=0.5) mutation carriers.

Conclusion:

This SNP is not a significant modifier of breast cancer risk for mutation carriers, though weak associations cannot be ruled out.

Comparison of statistical methods for estimating genetic admixture in a lung cancer study of African Americans and Latinos

A variety of methods are available for estimating genetic admixture proportions in populations; however, few investigators have conducted detailed comparisons using empirical data. The authors characterized admixture proportions among self-identified African Americans (n = 535) and Latinos (n = 412) living in the San Francisco Bay Area who participated in a lung cancer case-control study (1998-2003). Individual estimates of genetic ancestry based on 184 informative markers were obtained from a Bayesian approach and 2 maximum likelihood approaches and were compared using descriptive statistics, Pearson correlation coefficients, and Bland-Altman plots. Case-control differences in individual admixture proportions were assessed using 2-sample t tests and logistic regression analysis. Results indicated that Bayesian and frequentist approaches to estimating admixture provide similar estimates and inferences. No difference was observed in admixture proportions between African-American cases and controls, but Latino cases and controls significantly differed according to Amerindian and European genetic ancestry. Differences in admixture proportions between Latino cases and controls were not unexpected, since cases were more likely to have been born in the United States. Genetic admixture proportions provide a quantitative measure of ancestry differences among Latinos that can be used in analyses of genetic risk factors.