A population-based study of the Arg399Gln polymorphism in X-ray repair cross- complementing group 1 (XRCC1) and risk of pancreatic adenocarcinoma

XRCC1 (X-ray repair cross-complementing group 1) is a base excision repair protein that plays a central role in the repair of DNA strand breaks and base damage from a variety of endogenous and exogenous oxidants including tobacco smoke. One genetic polymorphism (G-->A, Arg-->Gln at codon 399) occurs within a poly(ADP-ribose) polymerase binding region and within the central breast cancer susceptibility gene 1 product COOH terminus domain of XRCC1. The variant 399Gln allele of XRCC1 has been associated with elevated biomarkers of DNA damage in human cells. We conducted an analysis of the Arg399Gln polymorphism in XRCC1 using genomic DNA, and questionnaire information from 309 cases of pancreatic adenocarcinoma and 964 controls that were part of a population-based, case-control study conducted in the San Francisco Bay Area between 1994 and 2001. We genotyped individuals using a mass spectrometry-based method. Because smoking and obesity are known and suspected pancreas cancer risk factors, and have been associated with DNA damage and oxidative stress in target tissues, we estimated odds ratios (ORs), interaction contrast ratios (ICRs), and 95% confidence intervals for the combined effects of XRCC1 genotype and smoking or body mass index (in kg/m(2)). We also assessed potential gene-gene interactions between polymorphisms in XRCC1 and CYP1A1, GSTT1, and GSTM1. We found little or no evidence for an association between XRCC1 genotype and pancreatic cancer among Caucasians, African-Americans, or Asians. There was evidence for interaction between XRCC1 399Gln and smoking that was stronger among women than men. Relative to never active or passive smokers with the Arg/Arg genotype, the age- and race-adjusted ORs and ICRs (95% confidence limits) for heavy smoking (>or=41 pack-years) were: for Gln/Gln or Arg/Gln genotypes [women OR = 7.0 (2.4, 21), ICR = 3.1 (0.03, 6.2); men OR = 2.4 (1.1, 5.0), ICR = 1.3 (-0.20, 2.8)]; and for the Arg/Arg genotype [women OR = 2.2 (0.73, 6.4); men OR = 1.5 (0.68, 3.2)]. Analyses of combined genotypes suggested an interaction between XRCC1 (Gln/Gln or Arg/Gln) and GSTT1/GSTM1-null/null among women but not among men. There was no evidence of interaction between XRCC1 genotype and body mass index. Our results suggest that the XRCC1 399Gln allele is a potentially important determinant of susceptibility to smoking-induced pancreatic cancer. Our findings, including stronger associations and interactions among women, require replication in additional study populations.     

Evaluation of DNA repair gene XRCC1 polymorphism in prediction and prognosis of hepatocellular carcinoma risk

We conducted a case-control study in China to clarify the association between XRCC1-Arg399Gln polymorphism and HCC risk. A total of 150 cases and 158 controls were selected from the the Affiliated Hospital of Qingdao University from May 2008 to May 2010. XRCC1-Arg399Gln polymorphism was based upon duplex polymerase-chain-reaction with the confronting-two-pair primer (PCR-CTPP) method. All analyses were performed using the STATA statistical package. A significantly increased risk was associated with the Arg/Gln genotype (adjusted OR 1.78, 95%CI=1.13-2.79) compared with genotype Arg/Arg. In contrast, the Gln/Gln genotype had non-significant increased risk of HCC with adjusted OR (95%CI) of 1.69 (0.93-2.66). A significant association was found between positive HBsAg and Arg/Gln, with an OR of 3.43 (95% CI=1.45-8.13). Patients carrying Gln/Gln genotypes showed significantly lower median survival than Arg/Arg genotypes (HR=1.38, 95% CI=1.04-1.84). Further Kaplan-Meier analysis showed decreased median survival in Arg/Gln+Gln/Gln genotype carriers in comparison to Arg/Arg carriers (HR=1.33, 95% CI=1.02-1.76). In conclusion, we observed that XRCC1-Arg399Cln polymorphism is associated with susceptibility to HCC, and XRCC1 Gln allele genotype showed significant prognostic associations.     

肝细胞癌患者的谷胱甘肽硫转移酶基因缺失的研究

目的　研究广西黄曲霉毒素B1(AFB1)高污染区人群谷胱甘肽硫转移酶GSTM 1和GSTT1基因缺失多态性与肝细胞癌高发的相关性。方法　采用聚合酶链反应 (PCR)方法检测 110例高污染区肝细胞癌患者和 135例无癌健康对照者的GSTM1和GSTT1基因型分布。结果　正常对照组GSTM 1和GSTT1基因缺失率分别为 4 7.4 %和 4 0 .7% ,肝细胞癌组GSTM 1和GSTT1基因缺失率分别为 6 3.6 %和 6 0 .0 % ;GSTM 1基因缺失在肝细胞癌组和正常对照组之间 ,差异具有显著性意义 (P <0 .0 5 ) ;GSTT1基因缺失在肝细胞癌组和正常对照组之间差异具有非常显著性意义 (P <0 .0 1)。结论　肝细胞癌患者GSTM1和GSTT1基因缺失水平偏高可能是易感的原因之一。     

Polymorphism of DNA repair gene XRCC1 and hepatocellular carcinoma risk in Chinese population

Aim: We conducted a case-control study in China to clarify the association between the XRCC1-Arg399Gln polymorphism and HCC risk. Methods: A total of 202 cases and 236 controls were selected from the the Affiliated Hospital of Qingdao University from May 2008 to May 2010. Assessment of the XRCC1-Arg399Gln polymorphism was based upon duplex polymerase-chain-reactions with the confronting-two-pair primer (PCR-CTPP) method. All analyses were performed using the STATA statistical package. Results: A significant increase in risk was associated with the Arg/Gln genotype (adjusted OR 1.55, 95%CI=1.03-2.57) compared with Arg/Arg. However, the Gln/Gln genotype had non-significant increased risk of HCC with adjusted OR (95%CI) of 1.34(0.67-2.38). There was also a significant increasewith the Arg/Gln genotype among HCC patients above 50 years old (OR=1.95, 95% CI=1.14-3.57). Additionally, the risk of HCC was moderately increased in drinkers with Arg/Gln genotype compared with never drinkers, and the adjusted OR (95% CI) was 1.89 (1.13-3.45). Conclusion: This study demonstrated that a polymorphism in a DNA repair gene may influence the risk of HCC. The XRCC1 codon Arg/Gln was thuis associated with an increased risk of HCC, especiallyin patients above 50 years old and/or with a drinking habit.     

肝细胞癌、鼻咽癌患者谷胱甘肽硫转移酶m和T1基因型分布

Objective: The aim of our study was to investigate the distribution of glutathione-S-transferase M1 (GSTM1) and T1 (GSTT1) gene polymorphism in hepatocellular carcinoma (HCC) and nasopharyngeal carcinoma (NPC) patients in a high risk area in Guangxi Zhuang Autonomous Region, China.Methods: It was a case-control study.The genotypes of GSTM1 and GSTT1 in 181 HCC and 126 NPC patients were compared with 641 matched control.The GSTM1 and GSTT1 genotypes were detected using conventional multiplex PCR method.Results: The frequency of GSTM1 null genotype in HCC, NPC and control groups were 65.2%, 61.9% and 47.6% respectively, significant difference between these two cancer groups and control was observed (P < 0.01).The frequency of GSTT1 null genotype in HCC, NPC and control groups were 57.5%, 62.7% and 43.1% respectively, significant difference between these two cancer groups and control was observed (P < 0.01).Conclusion: The distributions of GSTM1 and T1 genes are polymorphic in HCC and NPC patients in a high risk area in Guangxi, individuals with GSTM1-null or GSTT1-null would have an increasing risk of developing HCC and NPC, especially when combination with virus infection (HBV or EBV) and absorbed chemical toxin (AFB1 or cigarette).     

Hepatocellular carcinoma and polymorphisms in carcinogen-metabolizing and DNA repair enzymes in a population with aflatoxin exposure and hepatitis B virus endemicity.

High rates of hepatocellular carcinoma (HCC) in The Gambia, West Africa, are primarily due to a high prevalence of chronic hepatitis B virus infection and heavy aflatoxin exposure via groundnut consumption. We investigated genetic polymorphisms in carcinogen-metabolizing (GSTM1, GSTT1, HYL1*2) and DNA repair (XRCC1) enzymes in a hospital-based case-control study. Incident HCC cases (n = 216) were compared with frequency-matched controls (n = 408) with no clinically apparent liver disease. Although the prevalence of variant genotypes was generally low, in multivariable analysis (adjusting for demographic factors, hepatitis B virus, hepatitis C virus, and TP53 status), the GSTM1-null genotype [odds ratio (OR), 2.45; 95% confidence interval (95% CI), 1.21-4.95] and the heterozygote XRCC1-399 AG genotype (OR, 3.18; 95% CI, 1.35-7.51) were significantly associated with HCC. A weak association of the HYL1*2 polymorphism with HCC was observed but did not reach statistical significance. GSTT1 was not associated with HCC. The risk for HCC with null GSTM1 was most prominent among those with the highest groundnut consumption (OR, 4.67; 95% CI, 1.45-15.1) and was not evident among those with less than the mean groundnut intake (OR, 0.64; 95% CI, 0.20-2.02). Among participants who had all three suspected aflatoxin-related high-risk genotypes [GSTM1 null, HLY1*2 (HY/HH), and XRCC1 (AG/GG)], a significant 15-fold increased risk of HCC was observed albeit with imprecise estimates (OR, 14.7; 95% CI, 1.27-169). Our findings suggest that genetic modulation of carcinogen metabolism and DNA repair can alter susceptibility to HCC and that these effects may be modified by environmental factors.     

The association between polymorphisms in glutathione S-transferase (GSTM1 and GSTT1) and lung cancer outcome

BACKGROUND: Polymorphisms in the glutathione S-transferase (GST) family may be associated with increased risk of lung cancer, somatic changes in lung tumour tissue, and survival. We evaluated survival according to GST polymorphism in lung cancer patients. METHODS: We studied DNA polymorphisms of 81 primary lung cancer patients at 2 glutathione-related loci: GSTM1, and GSTT1 that encode glutathione S-transferase-mu, and glutathione S-transferase- square. The presences of the GSTM1 and GSTT1 genes were assayed by PCR. Kaplan-Meier with log rank tests, and Cox regression models were applied in the analysis. RESULTS: The median age of 75 males and 6 females was 60 years. Median survival of the whole population was 8 months. In the first presentation, none of the patients with GSTT1 null genotype but 30 percent of the patients with GSTT1-positive genotype had liver metastasis (p < 0.01) but GSTT1 genotype was not associated with survival. Sputum (p < 0.01) was more common in patients with GSTM1 null genotype. Subjects with the GSTM1-null genotype had shorter survival. Using a Cox proportional hazard model, GSTM1, tumor (T) factor and thoracic irradiation status were identified as independent prognostic factors. CONCLUSIONS: Our preliminary results showed that GSTM1-null genotype was associated with shorter survival.     

Association between glutathione S-transferase genotypes and Hodgkin's lymphoma risk and prognosis.

PURPOSE: The interplay between genetic susceptibility and exposure to carcinogens has been shown to be involved in the etiology of many solid tumors. We studied the frequency and clinical correlates of polymorphisms resulting in deletions of two genes involved in the detoxification of potentially carcinogenic agents, glutathione S-transferase (GST)-M1 and GSTT1 in patients with Hodgkin's lymphoma (HL). EXPERIMENTAL DESIGN: The prevalence of gene deletions in 90 patients with HL was compared with a case-matched cohort of 176 normal blood donors. GST gene polymorphisms were studied using a multiplex PCR method, including the BCL2 gene as an internal control. RESULTS: Deletions of the GSTT1 gene were more frequent in cases compared with controls (28.9 versus 17.6%, P = 0.04), resulting in an increased risk for HL in individuals with the GSTT1-null genotype (odds risk, 1.9; 95% confidence interval 1.04-3.46). The GSTT1-null genotype particularly increased the HL risk in females aged <45 years (odds risk 6.1, 95% confidence interval 1.6-23, P = 0.008). Correlating patient characteristics to genotype, we found an association between the GSTT1-null genotype and a limited stage of disease (I/IIA versus IIB-IV, 40.6 versus 19.6%, P = 0.047) and an erythrocyte sedimentation rate of <50 mm/h (P = 0.02). Patients with at least one GST deletion (GSTM1- or GSTT1-) had a significant better disease-free survival when compared with those with undeleted GST genes (GSTM1+/GSTT1+; P = 0.012). CONCLUSIONS: The GSTT1-null genotype may increase the risk for HL and is associated with favorable prognostic factors, and the presence of at least one GST deletion indicates an improved disease-free survival.     

Association of XPD and XRCC1 Genetic Polymorphisms with Hepatocellular Carcinoma Risk

Aim: XRCC1 and XPD are two major repair genes involved in nucleotide excision repair (NER), whichis reported to be associated with risk of several cancers. We explored the association of XRCC1 and XPDpolymorphisms with the risk of HCC. Methods: A total of 410 cases with HCC and 410 health controls werecollected. XRCC1 Arg194Trp, XRCC1 Arg399Gln, XPD Lys751Gln and XPD Asp312Asn genotyping wasperformed by duplex polymerase-chain-reaction with the confronting-two-pair primer (PCR-CTPP) method.Results: XRCC1 194Trp/Trp was strongly significantly associated with an increased risk of HCC cancer whencompared with the wide-type genotype (OR=2.26, 95% CI=(1.23-5.38). Individuals carrying the XRCC1 399Gln/Gln showed increased risk of HCC (OR=1.74, 95%CI=1.06-2.74). The XPD 751Gln/Gln and Gln allele genotypewere associated with strong elevated susceptibility to HCC (OR=3.51 and 1.42, respectively). Conclusion: Theseresults suggest that polymorphisms in XRCC1 and XPD may have functional significance in risk of HCC.     

Lack of Associations between Genetic Polymorphisms in GSTM1, GSTT1 and GSTP1 and Pancreatic Cancer Risk: A Multi-Institutional Case-Control Study in Japan

Background: We aimed to evaluate the role of genetic polymorphisms in tobacco carcinogen-metabolizinggenes and their interactions with smoking in a hospital-based case-control study of Japanese subjects. Materialsand Methods: We examine the associations of pancreatic cancer risk with genetic polymorphisms in GSTM1,GSTT1 and GSTP1, phase II enzymes that catalyze the conjugation of toxic and carcinogenic electrophilicmolecules. The study population consisted of 360 patients and 400 control subjects, who were recruited fromseveral medical facilities in Japan. Unconditional logistic regression methods were used to estimate odds ratios(ORs) and 95% confidence intervals (CIs) for the associations between genotypes and pancreatic cancer risk.Results: Among the control subjects, the prevalence of the GSTM1-null genotype and the GSTT1-null genotypewas approximately 56% and 48%, respectively. Cases and controls were comparable in terms of GSTM1 andGSTT1 genotype distributions. Neither of the deleted polymorphisms in GSTM1 and GSTT1 was associated withthe risk of pancreatic cancer, with an age- and sex-adjusted OR of 0.99 (95%CI: 0.74-1.32) for the GSTM1-nullgenotype, and 0.98 (95%CI: 0.73-1.31) for the GSTT1-null genotype. The OR was 0.97 (95%CI: 0.64-1.47) forindividuals with the GSTM1 and GSTT1-null genotypes compared with those with the GSTM1 and GSTT1-present genotypes. No synergistic effects of smoking or GST genotypes were observed. Conclusions: Our resultsindicate no overall association between the GSTM1 and GSTT1 deletion polymorphisms and pancreatic cancerrisk in the Japanese subjects in our study.     

广西扶绥县肝癌家系XRCC1基因Arg399Gln多态性与肝细胞癌的遗传易感性

目的研究广西扶绥县肝癌家系人群DNA修复基因XRCC1Arg399Gln多态性与肝细胞癌（HCC）遗传易感性的相关性。方法采用病例-对照研究方法,对扶绥县21个肝癌家系人群和10个正常家系人群,运用PCR-RFLP方法分析XRCC1基因Arg399Gln位点多态性,并应用Logistic回归模型分析该位点多态性与肝细胞癌遗传易感性的关系。结果通过XRCC1Arg399Gln基因型检测分型,肝癌家系人群携带变异等位基因Gln的频率为23.68%,正常家系人群为13.16%,等位基因在两组间的分布差异无统计学意义（P〉0.05）。基因型分布符合Hardy-Weinberg平衡定律。正常家系人群中携带Arg/Gln者发生HCC的风险是携带Arg/Arg者的1.622倍（95%CI=0.475～5.541,P=0.440）。肝癌家系人群中除肝癌患者外,携带Arg/Gln、Gln/Gln者发生HCC的风险分别是携带Arg/Arg者的1.198倍（95%CI=0.362～3.968）和2.964倍（95%CI=0.434～20.220,P分别为0.768、0.267）。结论广西扶绥县肝癌家系人群中,XRCC1399Arg/Gln基因型和Gln/Gln基因型者患HCC的风险较Arg/Arg基因型者有增加的趋势,但不存在显著相关性。     

MS-920: DNA repair gene polymorphisms, diet and colorectal cancer risk in Taiwan

This hospital-based case-control study examined whether polymorphic DNA repair genes: XRCC1 Arg399Gln, XRCC3 Thr241Met and XPD Lys751Gln, play a role in the susceptibility to colorectal cancer. We genotyped these polymorphisms for 727 newly diagnosed colorectal adenocarcinoma cases and 736 age and sex matched healthy controls in Taiwan. Although the colorectal cancer risk was not significantly associated with these genes, the risk was significantly elevated in younger subjects (< or =60 years) with the XRCC1 399Arg/Arg genotype compared to those with XRCC1 399Gln allele (OR=1.46, 95% CI=1.06-2.99, P=0.02). The stratified analysis showed that XRCC3 interacted with meat consumption (P for interaction=0.02), but was limited to the low meat consumption (OR=2.34, 95% CI=1.28-4.29). Our results suggest that the XRCC1 Arg399Gln polymorphism may contribute to the risk of early-onset colorectal cancer and the XRCC3 Thr241Met polymorphism may modify the risk for meat-associated colorectal cancer.     

X-RAY REPAIR CROSS-COMPLEMENTING GROUP 1 （XRCC1） Arg 399 Gin POLYMORPHISM AND AFLATOXIN B1 （AFB1）-RELATED HEPATOCELLULAR CARCINOMA （HCC） IN GUANGXI POPULATION

In Guangxi Zhuang Autonomous Region,Hepatocellular carcinoma(HCC)is one of the maincancer killers,the incidence rate of which is5～40/1,000,000per year.Clinic-epidemiological evidencesuggests AFB1exposure is the most cause[1].However,the exact mechanisms of AFB1hepatocarcinogenesishave not been fully elucidated.Recently,there is agrowing realization that genetic constitution is ofimportance in determining individual’s susceptibility toHCC.This genetic susceptibility may result frominhe…     

Implication of Polymorphisms in DNA Repair Genes in Prognosis of Hepatocellular Carcinoma

XRCC1 genetic polymorphisms could be associated with increased risk of various cancer, includinghepatocellular carcinoma (HCC), the fifth most common cancer. We here conducted a study to explore the roleof selective SNPs of the XRCC1 and XPD genes in the prognosis of HCC. A total of 231 cases were collected, andgenotyping of XRCC1 Arg194Trp, XRCC1 Arg399Gln, XPD Lys751Gln and XPD Asp312Asn was performedby duplex polymerase-chain-reaction with the confronting-two-pair primer method. Our findings indicatedXRCC1 399Gln/Gln genotype was associated with a significant difference in the median survival time comparedwith patients carrying Arg/Trp and Arg/Arg genotypes, and individuals with XPD 751 Gln/ Gln genotype had asignificantly greater survival time than patients carrying Lys/Lys and Lys/Gln genotypes. The Cox’s regressionanalysis showed individuals carrying XRCC1 399Trp/Trp genotype had 0.55 fold risk of death from HCC thanArg/Arg genotype. Similarly, XPD 751Gln/Gln had a strong decreasein comparison to XPD Lys/Lys carriers withan HR of 0.34. These results suggest that polymorphisms in XRCC1 and XPD may have functional significancein the prognosis of HCC.     

The role of GSTM1 and GSTT1 polymorphisms in head and neck cancer risk

Head and neck cancer (HNC) is a serious health problem worldwide and tobacco smoke is a main causative factor for this malignancy. Interindividual genetic differences in enzymes involved in the metabolism of tobacco smoke carcinogens are one of the most important risk factors in the development of HNC. GSTM1 and GSTT1 enzymes participate in detoxifying of tobacco smoke carcinogens and have deletion polymorphisms. We performed a case control study to investigate a possible association between GSTM1 and GSTT1 variants and HNC risk. A total of 98 HNC cases, all of which were squamous cell carcinoma, and 120 healthy controls were investigated. GSTM1 and GSTT1 polymorphisms were genotyped using PCR. There was a significant association between HNC and GSTM1-null genotype (adjusted OR: 2.36, 95% CI: 1.303-4.26, p = 0.005). The frequency overall of GSTT1-null genotypes was not significant in HNC patients compared with that of GSTT1-positive genotypes (adjusted OR: 1.16, 95% CI: 0.563-2.397, p = 0.686). No combined effect was observed for GSTM1 and GSTT1 genotypes. When data were stratified by smoking status, cases having GSTM1-null genotype who were smokers conferred the highest risk (adjusted OR: 4.06, 95% CI: 1.3-12.63). Thus, our results suggest that GSTM1 polymorphism may significantly increase the risk of HNC and there is an additive interaction between GSTM1-null genotype and smoking on HNC risk.     

An Updated Meta-analysis on the Association of X-Ray Repair Cross Complementing Group 1 Codon 399 Polymorphism with Hepatocellular Carcinoma Risk

Background: A number of studies have reported the association of X-ray repair cross-complementing group1 (XRCC1) Arg399Gln polymorphism with susceptibility to hepatocellular carcinoma (HCC). However, theresults were inconsistent and inconclusive. The aim of this study was to comprehensively explore the associationof XRCC1 Arg399Gln variant with HCC risk. Materials and Methods: Systematic searches of PubMed, Elsevier,Science Direct, CNKI and Chinese Biomedical Literature Database were performed. Pooled odds ratio (OR)with 95% confidence intervals (CI) was calculated to estimate the strength of association. Results: Overall,we observed an increased HCC risk among subjects carrying XRCC1 codon 399 Gln/Gln, Arg/Gln and Gln/Gln+Arg/Gln genotypes (OR=1.20, 95%CI: 1.05-1.38, OR=1.16, 95%CI: 1.05-1.28, and OR=1.14, 95%CI:1.04-1.24, respectively) based on 20 studies including 3374 cases and 4633 controls. In subgroup analysis, weobserved an increased risk of XRCC1 codon 399 Gln/Gln, Arg/Gln and Gln/Gln+Arg/Gln polymorphisms forHCC in hospital-based study (OR=1.25, 95%CI: 1.03-1.51, OR=1.21, 95%CI: 1.07-1.36 and OR=1.18, 95%CI:1.06-1.31, respectively) and in Asian population (OR=1.19, 95%CI: 1.03-1.38, OR=1.17, 95%CI: 1.04-1.30 andOR=1.14, 95%CI: 1.04-1.25, respectively). Limiting the analysis to the studies with controls in agreement withHardy-Weinberg equilibrium (HWE), we observed an increased HCC risk among Gln/Gln, Arg/Gln and Gln/Gln+Arg/Gln genotype carriers (OR=1.17, 95%CI: 1.05-1.29, OR=1.12, 95%CI: 1.00-1.25 and OR=1.11, 95%CI:1.02-1.21, respectively). Conclusions: This updated meta-analysis results suggest that XRCC1 Arg399Gln variantsmay contribute to HCC risk. Well-designed studies with larger sample size were required to further verify ourfindings.     

Glutathione S-transferase M1 and T1 genetic polymorphisms,alcohol consumption and breast cancer risk

Alcohol consumption has been inconsistently associated with breast cancer risk. Recent studies suggest that genetic polymorphisms of glutathione S-transferases (GSTs) may modify this relation. To determine if breast cancer risk is associated with GSTM1 and GSTT1 genetic polymorphisms, and to evaluate the effect modification between GST genotypes and alcohol consumption in the risk of breast cancer, we conducted a case-control study in the state of Connecticut in the period 1998 and 2001. Cases were histologically confirmed, incident breast cancer patients in New Haven County, CT. Controls were randomly selected from women histologically confirmed to be without breast cancer. The study results show that, while GSTM1 genotypes were not associated with breast cancer risk, GSTT1-null genotype was associated with a significant 90% increased risk for postmenopausal women (OR=1.9, 95% CI 1.2-3.0). Analysis by GST genotypes and alcohol consumption shows that GSTM1A ever-drinking women had a 2.5-fold (OR=2.5, 95% CI 1.1-5.5) increased risk of breast cancer compared to the GSTM1A never-drinkers, and the risk increases with duration and daily amount of alcohol consumption. Postmenopausal women with GSTT1-null genotype, who consumed a lifetime of >250 kg of spirit-equivalents, had an almost seven-fold increased risk (OR=6.8, 95% CI 1.4-33.9), and drinking commencing at younger ages appears to carry a higher risk. An OR of 8.2 (95% CI 1.2-57.4) was observed for those with GSTM1A, and GSTT1-null genotypes who had consumed a lifetime of >250 kg of spirit-equivalents. In conclusion, alcohol consumption may increase breast cancer risk among those who carry susceptible GST genotypes.     

Polymorphisms of DNA repair gene XRCC1 and hepatocellular carcinoma risk among East Asians: a meta-analysis

Association studies on the X-ray repair cross-complementing group 1 (XRCC1) polymorphisms (Arg194Trp, Arg280His, and Arg399Gln) in hepatocellular carcinoma (HCC) have shown conflicting results. The aim of this study was to quantitatively summarize the evidence for such a relationship. Published literatures from PubMed, Embase, CNKI, and Chinese Biomedicine Database were retrieved. Pooled odds ratio (OR) with 95 % confidence interval (CI) was calculated using fixed- or random-effects model. Thirteen studies including 3,011 HCC cases and 3,619 controls were included in the meta-analysis of the association between XRCC1 Arg399Gln polymorphism and HCC risk. The results indicated that Arg399Gln polymorphism was significantly associated with risk of HCC in a codominant model (Gln/Gln vs. Arg/Arg, OR?=?1.32, 95 % CI?=?1.08–1.61; Arg/Gln vs. Arg/Arg, OR?=?1.41, 95 % CI?=?1.12–1.80) and a dominant model (Gln/Gln?+?Arg/Gln vs. Arg/Arg, OR?=?1.39, 95 % CI?=?1.15–1.69), but not in a recessive model (Gln/Gln vs. Arg/Gln?+?Arg/Arg, OR?=?1.13, 95 % CI?=?0.95–1.35). Limiting the analysis to the studies within Hardy–Weinberg equilibrium, the results were persistent and robust. When stratifying for region and source of controls, persistent results were observed in any subgroup. No evidence of association of Arg194Trp (980 HCC cases and 966 controls) and Arg280His (1,200 HCC cases and 1,236 controls) with HCC risk was found. No publication bias was found in the present study. The results from the present meta-analysis indicated that the Arg399Gln polymorphisms of XRCC1 may be a genetic susceptibility for HCC in the East Asian population. Further, large and well-designed studies are needed to confirm this conclusion.     

Updated Assessment of the Association of the XRCC1 Arg399Gln Polymorphism with Lung Cancer Risk in the Chinese Population

Background: Published studies have reported relationships between X-ray repair cross-complementing group1 (XRCC1) Arg399Gln polymorphism and lung cancer risk in Chinese population. However, the epidemiologicalresults remained controversial. The objective of this study was to clarify the association of XRCC1 Arg399Glnpolymorphism with lung cancer risk in the Chinese population. Materials and Methods: Systematic searches wereperformed through the database of Medline/Pubmed, Web of Science, Embase, CNKI and WanFang MedicalOnline. Odds ratios (ORs) with 95% confidence interval (95%CI) were calculated to estimate the strength ofthe association. Results: Overall, we observed an increased lung cancer risk among subjects carrying XRCC1codon 399 Gln/Gln genotype (OR=1.36, 95%CI: 1.09-1.71) in the Chinese population on the basis of 19 studieswith 5,416 cases and 5,782 controls. We did not observe any association between XRCC1 codon 399 Arg/Gln andArg/Gln+Gln/Gln polymorphisms and lung cancer risk (OR=1.00, 95%CI: 0.92-1.08 and OR=1.05, 95%CI: 0.97-1.13, respectively). Limiting the analysis to studies with controls in agreement with Hardy-Weinberg equilibrium(HWE), we observed an increased lung cancer risk among subjects carrying XRCC1 codon 399 Gln/Gln genotype(OR=1.18, 95%CI: 1.01-1.38). When stratified by source of control, we observed an increased lung cancer riskamong subjects carrying XRCC1 codon 399 Arg/Gln+Gln/Gln genotype on the basis of hospitalized patient-basedcontrols (OR=1.21, 95%CI: 1.04-1.42) and among subjects carrying XRCC1 codon 399 Gln/Gln genotype onthe basis of healthy subject-based controls (OR=1.22, 95%CI: 1.04-1.43). Conclusions: Our findings indicatedthat certain XRCC1 Arg399Gln variants might affect the susceptibility of lung cancer in Chinese population.Larger sample size studies are required to confirm our findings.     

A population-based, case-control study of polymorphisms in carcinogen-metabolizing genes, smoking, and pancreatic adenocarcinoma risk

BACKGROUND: Cigarette smoking is associated with a twofold increased risk of pancreatic cancer. We conducted a population-based case-control study in six San Francisco Bay area counties from 1994 to 2001 to investigate associations between polymorphisms in genes for two carcinogen-metabolizing enzymes (cytochrome P450 1A1 [CYP1A1] and glutathione S-transferase [GST]), smoking, and adenocarcinoma of the exocrine pancreas. METHODS: We used polymerase chain reaction-based methods to analyze blood samples obtained from 309 case subjects and 964 control subjects to determine their genotypes for three CYP1A1 polymorphisms (m1, m2, and m4) and for homozygous deletions of two GST genes, GSTM1 and GSTT1. Control subjects were frequency matched to case subjects by age and sex. All statistical tests were two-sided. RESULTS: None of the genetic polymorphisms themselves affected the risk of pancreatic cancer among Caucasian study participants. However, we observed an interaction between GSTT1-null genotype and cigarette smoking among Caucasians that was more prominent among women than among men. Relative to never smokers with the GSTT1-present genotype, the age-adjusted odds ratios (ORs) of pancreatic cancer for heavy smokers with the GSTT1-null genotype were 5.0 (95% confidence interval [CI] = 1.8 to 14.5) for women and 3.2 (95% CI = 1.3 to 8.1) for men; for heavy smokers with the GSTT1-present genotype they were 2.0 (95% CI = 1.0 to 4.0) for women and 2.1 (95% CI = 1.1 to 3.9) for men. ORs for pancreatic cancer among heavy smokers with both GSTT1-null and GSTM1-null genotypes were similar in magnitude to those among heavy smokers with the GSTT1-null genotype alone. There was no evidence of an interaction between CYP1A1 polymorphisms and smoking. CONCLUSIONS: The combination of heavy smoking and a deletion polymorphism in GSTT1 is associated with an increased risk of pancreatic cancer among Caucasians, with the associations possibly stronger in women than in men.