Polymorphisms in DNA repair gene XRCC1 and increased genetic susceptibility to glioma

Background: The XRCC1 gene encodes the XRCC1 protein, which complexes with three other DNA repair enzymes involved in the base-excision repair (BER) pathways. Different XRCC1 polymorphisms may increase the risk of cancers by impairing interaction with other enzymatic proteins and consequently altering DNA repair activity, and result in carcinogenesis. Our study aimed to investigate any association between three polymorphisms of the XRCC1 gene at codon 194, 280 and 399 and potential glioma risk. Methods: We collected 127 patients with primary glioma and 249 controls who requested general health examinations from Union Hospital of Tongji Medical College hospital from March 2007 to September 2010. A total of 5 ml venous blood was drawn from each subject. The polymorphisms of XRCC1 gene at codons 194, 280 and 399 were analyzed based on duplex polymerase-chain-reactions with the confronting-two-pair primer (PCR-CTPP) method. Results: The homozygous Trp/Trp and heterozygotes Arg/Trp variants of codon 194 had a 2.12 fold and 1.46 fold increased risk of glioma compared to the homozygous Arg/Arg wide genotypes. The same effect was found in codon 399, the codon 399 Gln/Gln and Arg/Gln genotypes being associated with a 2.24 fold and 1.67 fold increased risk in glioma. When comparing the codon 194 Arg/Arg and 399 Arg/Arg genotypes, the combination of codon 194 Trp allele and 399 Gln allele had a heavy increase in glioma risk (OR=2.87, 95%CI=1.56-6.73). Conclusion: The present study provided evidence of a potential role for XRCC1 codon 194 and 399 polymorphisms in genetic predisposition to glioma among the Chinese population. This analysis of correlation of DNA repair genes and glioma may provide a deeper insight into the genetic and environment factors for cancer risk.     

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.     

Association of DNA repair gene XRCC1 polymorphisms with head and neck cancer in Korean population

Squamous cell carcinoma of the head and neck (SCCHN), which is relatively prevalent in Korea, is believed to be induced by environmental carcinogens and host genetic factors. Accumulating evidence has shown that genetic differences in DNA repair capacity resulting from genetic polymorphism influence the risk of environmental carcinogenesis. We therefore examined the associations of genetic polymorphisms in the DNA repair genes XRCC1 with the risk of SCCHN in a Korean population (hospital-based, case-control study; 147 cases and 168 controls). Three known polymorphisms in the XRCC1 gene were genotyped: R194W(C>T) in exon 6, R280H(G>A) in exon 9 and R399G(G>A) in exon 10. Although no significant associations were apparent with R280H(G>A) and R399G(G>A), a highly significant association (p = 0.0005) of R194W(C>T) with the increased risk (OR = 2.61; 95% CI 1.53-4.46) of SCCHN was detected among patients and normal controls under dominant model. The frequency of minor allele-containing genotypes (TT and CT) was much higher in SCCHN patients (51.8%) compared to that in normal controls (30.3%) (p = 0. 0005). When considering a relatively small number of cases (n = 147) and controls (n = 168) in our study, larger studies are needed to validate the genetic effects of XRCC1 polymorphisms in Asian populations. In conclusion, the result from our study provides additional evidence of an association of the XRCC1 polymorphism (Arg194Trp) with SCCHN as markers of genetic susceptibility in the Korean population.     

XRCC1 Arg399Gln基因多态性与中国人群肝细胞癌易感性的Meta分析

目的 探讨XRCC1 Arg399Gln基因多态性与肝细胞癌（HCC）易感性的关系。方法 计算机检索PubMed、中国生物医学文献（CBM）、中国知网、万方及维普等数据库,收集有关XRCC1 Arg399Gln基因多态性与HCC易感性关系的病例对照研究,提取纳入文献的相关数据进行Meta分析,以病例组与对照组XRCC1 Arg399Gln各种基因模型的比值比（OR）为效应指标,发表偏倚采用Eggers检验和Beggs检验。结果 共17篇文献符合纳入标准,累计病例数3301例,对照组4156例。XRCC1 Arg399Gln基因多态性与中国人群HCC易感性有明显关联性（G/G vs. A/A：OR=1.32,95％CI：1.13～1.54,P=0.000;A/G vs. A/A：OR=1.25,95％CI：1.10～1.41,P=0.000;A/G+G/G vs. A／A：OR=1.22,95％CI：1.09～1.36,P=0000;G／G vs. A／A+A／G：OR=1.20,95％CI：1.04～1.39,P=0.014）。根据健康对照组来源不同的亚组分析中,所有地区或者控制人口来源医院的研究结果均显示,XRCC1 Arg399Gln 基因多态性与HCC易感性有明显关联性,但控制人口非医院来源的研究结果显示XRCC1 Arg399Gln 基因多态性与HCC易感性无明显关联性;根据地区不同分组的亚组分析中,在广西地区,除隐性遗传模型外（G/G vs. A/A+A/G：OR=1.25,95％CI：0.95～1.65,P=0.115）,其余遗传模型结果显示XRCC1 Arg399Gln基因多态性与广西地区HCC易感性有明显相关性（G/G vs. A/A：OR=1.47,95％CI：1.10～1.95,P=0.009;A/G vs. A/A：OR=1.35,95％CI：1.17～1.56,P=0.000;A/G+G/G vs.A／A：OR=133,95％CI：1.16～1.52,P=0.000）。结论 XRCC1 Arg399Gln 基因多态性可能增加中国人群HCC的易感性,尤其在广西地区。     

Polymorphisms of DNA repair gene XRCC1 and risk of glioma: a case-control study in Southern China

Objective: This study aimed to examine associations between polymorphisms in the X-ray cross-complementing group 1 (XRCC 1) gene and risk of glioma in a Chinese population. Methods: We performed a hospital-based case-control study with 271 cases and 289 controls in Guangdong province, China. Cases were patients newly diagnosed with pathologically confirmed glioma in two hospitals between June 2006 and May 2010. Controls were individuals without cancer, frequency matched by sex and age. Three SNPs in XRCC1 gene, Arg399Gln (rs25487), Arg194Trp (rs1799782) and Arg280His (rs25489), were analyzed by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) based method. Unconditional logistic regression was used to estimate the odds ratios (ORs) of polymorphisms in XRCC1 gene for glioma. Results: The Arg399Gln polymorphism was significantly associated with risk of glioma. Individuals with the Gln/Gln genotype had a significantly increased likelihood of developing glioma compared with those with the Arg/Arg genotype (adjusted OR = 1.93, 95% CI: 1.04 - 3.58), especially among males and individuals aged 50 years or older. Conclusion: The XRCC1 Arg399Gln polymorphism may be a useful susceptibility biomarker for glioma. Further studies in Chinese populations with larger sample sizes are now warranted.     

Polymorphisms of DNA repair genes XRCC1 and XPD and their associations with risk of esophageal squamous cell carcinoma in a Chinese population

Esophageal squamous cell carcinoma (ESCC), which is prevalent in China, is believed to be induced by environmental carcinogens. Accumulating evidence has shown that individual variation in DNA repair capacity resulting from genetic polymorphism influences risk of environmental carcinogenesis. We therefore investigated the associations between genetic polymorphisms in the DNA repair genes XRCC1 (Arg194Trp and Arg399Gln) and XPD (Asp312Asn and Lys751Gln) and risk of ESCC in an at-risk Chinese population. Genotypes were determined by a PCR-based approach in 433 patients with ESCC and 524 frequency-matched normal controls. We found that individuals with Trp/Trp genotype at XRCC1 Arg194Trp site had a 2-fold increased risk of this disease compared to Arg/Arg genotype (adjusted OR = 1.98; 95% CI 1.26-3.12). Furthermore, when compared to Arg/Arg and Arg/Trp genotype combined, homozygote for Trp/Trp genotype significantly increased the risk of developing ESCC, with the adjusted OR being 2.07 (95% CI 1.34-3.20). However, the XRCC1 Arg399Gln polymorphism was not significantly associated with risk of ESCC, with the adjusted OR being 0.87 (95% CI 0.55-1.37). Neither Asp312Asn nor Lys751Gln polymorphisms in the XPD gene influenced risk of ESCC in our study. These findings suggest that DNA repair gene XRCC1 but not XPD might play a role in esophageal carcinogenesis and might represent a genetic determinant in the development of the cancer.     

XRCC1单核苷酸多态性与结直肠癌风险的关系

背景与目的:X线交叉互补基因1(X-ray repair cross complementing group 1,XRCC1)编码蛋白在DNA单链断裂修复和DNA碱基修复过程中起重要作用.该基因外显子多态性的存在可影响编码蛋白的功能活性,最终使机体对癌症的易感性发生变化.本研究旨在探讨该基因外显子最常见的3处单核苷酸多态(single nucleotide polymorphism,SNP)--C26304T、G27466A和G28152A与结直肠癌风险的关系.方法:以聚合酶链反应(polymerase chain reaction,PCR)和限制性片段长度多态性(restrictive fragment length polymorphism,RFLP)分析方法,检测207例结直肠癌病例和621例成组匹配的正常对照XRCC1 C26304T、G27466A和G28152A基因型,并比较不同基因型与结直肠癌风险的关系.采用EH Linkage Software 1.2统计分析软件对研究对象的单体型分布进行预测.结果:年龄、性别、身体质量指数(body mass index,BMI)等个体特征,以及吸烟、饮酒等常见环境暴露因素的分布和/或构成比在结直肠癌病例组和对照组间差异均无显著性(P＞0.05).对XRCC1各多态基因型检测分型发现,结直肠癌病例组携带26304T、27466A和28152A变异等位基因的频率分别为29.95%、11.22%和28.22%,对照组分别为32.87%、12.34%和27.27%,各多态等位基因在两组间分布均没有显著性差异(P＞0.05).各多态基因型分布经x2拟合优度检验均符合Hardy-Weinberg平衡定律,且在两组间都没有显著性差异(P＞0.05).没有观察到各多态基因型与结直肠癌发病风险存在显著相关关系(P＞0.05).单体型分析发现,各变异等位基因在病例组和对照组内均存在遗传连锁不平衡现象,CGG、CGA、CAG和TGG是最常见的4类单体型,其在两组的分布频率总和分别为95.54%和96.64%,然而在两组间同样不存在显著性差异(P＞0.05).结论:我国浙江省嘉善县人群中,XRCC1 C26304T、G27466A和G28152A基因多态性与结直肠癌发病风险不存在相关性,然而各变异等位基因存在遗传连锁不平衡现象,CGG、CGA、CAG和TGG是最常见的4类单体型.     

XRCC1 and hOGG1 genes and risk of nasopharyngeal carcinoma in North African countries

Although genetic susceptibility to nasopharyngeal carcinoma (NPC) has been recognized for a long time, little is known about the responsible genes. X-Ray repair cross-complementing protein 1 (XRCC1) and human 8-oxo-guanine glycosylase 1 (hOGG1) genes are involved in deoxyribonucleic acid (DNA) repair and were found associated with NPC risk in three Asian case-control studies. The objective of the present study was to test these genes in a sample from North Africa, one of the major NPC endemic regions in the world. Three single nucleotide polymorphisms (SNPs) in the XRCC1 gene and one SNP in the hOGG1 gene were genotyped in 598 NPC cases from Morocco, Algeria, and Tunisia and 545 controls frequency matched by recruitment center, age, sex, and urban/rural household. The genotype and allelic distributions for the hOGG1 (326)Ser/Cys SNP and for the XRCC1 (399)Arg/Trp, (280)Arg/His, and (194)Arg/Trp SNPs did not differ significantly among NPC cases and controls. The XRCC1 (194)Trp allele frequency was significantly lower in the North African population than in Asian population (f = 0.04 vs. 0.31 in Cantonese Chinese and 0.21 Han Chinese). The hOGG1 (326)Ser allele frequency was significantly higher in the North African population (f = 0.73) than in Asian populations (f = 0.39 in Taiwanese). The results of the present study obtained from a large sample indicate that the XRCC1 and hOGG1 genes are unlikely to play a role in the susceptibility to NPC in North Africans. Our results do not corroborate those found in Asian population on smaller samples.     

Genetic polymorphisms of DNA repair genes XRCC1 and XRCC3 and risk of colorectal cancer in Chinese population

Aim: The distribution of DNA repair gene XRCC1 and XRCC3 genotypes was used to assess the potential influence of genetic polymorphisms on risk of colorectal cancer, and interactions with other factors. Methods: a 1:2 matched case-control study was conducted with 485 cases and 970 controls. XRCC1 and XRCC2 genotype polymorphisms were based upon duplex polymerase-chain-reaction with the confronting-two-pairprimer (PCR-CTPP) method. Results:The XRCC1 399Cln allele polymorphism was found to be associated with an increased colorectal cancer risk, while an non-significant inversely association was noted for XRCC3 241Thr/Thr genotype. We also found that individuals with the XRCC1 399 Gln and XRCC3 241Met alleles had an elevated risk, while XRCC3241Thr/Thr was proctective. Conclusion: This study is the first to provide evidence of importance of XRCC1 and XRCC3 gene polymorphisms for risk of colorectal cancer in the Chinese population.     

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…     

XRCC1 Gene Polymorphism Increases the Risk of Hepatocellular Carcinoma in Egyptian Population

Several major risk factors for hepatocellular carcinoma (HCC) have been identified, including chronic infection of hepatitis B virus (HBV) and hepatitis C virus (HCV). Nevertheless, only a fraction of infected patients develops HCC during their lifetime suggesting that genetic factors might modulate HCC development. X-ray repair cross complementing group1 (XRCC1) participates in the repair pathways of DNA. Aim: to investigate the association between XRCC1 gene polymorphism and HCC in Egyptian chronic hepatitis C patients. Methods: This study was assessed on 40 patients with HCC secondary to chronic HCV infection who were compared to 20 cirrhotic HCV patients and 40- age and gender- matched healthy control group. After collection of relevant clinical data and basic laboratory tests, c.1517G>C SNP of XRCC1 gene polymorphism was performed by (PCR-RFLP) technique. Results: A statistically higher frequency of XRCC1 (CC, GC) genotypes and increased (C) allele frequency in patients with HCC was found in comparison to cirrhotic HCV patients as well as control group. In addition, patients with the XRCC1 (CC, GC) genotypes had significantly higher number and larger size of tumor foci and significantly higher Child Pugh grades. Multivariate analysis showed that the presence of c.1517G>C SNP of XRCC1 gene is an independent risk for the development of HCC in chronic HCV patients with 3.7 fold increased risk of HCC development. In conclusion: XRCC1 gene polymorphism could be associated with increased risk of HCC development in chronic HCV Egyptian patients.     

非小细胞肺癌NP方案化疗敏感性与DNA修复基因XRCC1多态性的关系

背景与目的:基因多态预测肿瘤化疗药物敏感性对肿瘤个体化治疗具有重要意义。本研究旨在探讨DNA修复基因XRCC1 codon194及399位点基因多态性与非小细胞肺癌长春瑞滨加顺铂(vinorelbine and cisplatin,NVB and DDP,NP)方案化疗敏感性的关系。方法:采用聚合酶链反应-限制性片段长度多态性技术检测164例非小细胞肺癌患者外周血DNAXRCC1194和399位点的多态性。选择NP方案化疗,化疗两周期后评价疗效,并分析化疗敏感性与基因多态性的关系。结果:携带XRCC1基因Codon194C/T+T/T基因型者化疗有效率(41.8%)是C/C基因型者(26.0%)的2.038倍(P=0.036,95%CI=1.044-3.976)。携带XRCC1基因Codon399G/G、A/G、A/A型的患者化疗有效率(37.1%,34.6%,14.3%)之间的差异无统计学意义(P>0.05)。应用分析软件SHEsis发现以     

XRCC1多态性与非吸烟女性肺腺癌易感性的关系

背景与目的XRCC1是一种DNA损伤修复基因，其单核苷酸多态性异常是导致DNA修复能力个体差异的重要原因，可能导致个体患肺癌的危险升高。本研究的目的是探讨XRCC1单核苷酸多态性与非吸烟女性肺腺癌易感性的关系。方法采用以医院患者为基础的病例对照研究方法，研究对象包括非吸烟女性肺腺癌患者126例和同期其它肺部疾病对照126例。以聚合酶链反应一限制性片段长度多态性方法分析XRCC1基因Arg399Gln多态性，比较不同基因型与非吸烟女性肺腺癌的关系，并探讨油烟暴露与基因多态交互作用对患癌风险的影响。结果与携带399Arg／Arg基因型者比较，携带399Gln／Gln基因型者患肺腺癌的风险是其8．695倍（95％CI为3．343～22．614）。携带等位基因399Gln又有油烟暴露的个体患肺腺癌的风险明显增高，校正的比值比为5．21（95％CI为1．85～14．70，P〈0．001）。结论XRCC1基因Arg399 Gln多态性可能是非吸烟女性肺腺癌的遗传易感因素。     

XRCC1基因G28152A多态与肺癌风险的研究

背景与目的 :研究碱基切除修复基因XRCC1基因G28152A单核苷酸多态与肺癌风险的关系。材料与方法 :以病例_对照研究方法 ,采用聚合酶链反应一限制性片段长度多态性法检测肺癌病例(n=149)和按性别、年龄频数匹配的正常对照(n=157)XRCC1基因G28152A多态 ,分析各基因型与肺癌易感性的关系。 结果 :肺癌患者中 ,XRCC1基因28152AA突变基因型频率为15.4 % ,高于对照组7.6 % ;此基因型个体发生肺癌风险是其他基因型个体的2.2倍(95 %CI1.06～4.61)。 结论 :XRCC1基因G28152A多态可能在肺癌发生中起一定作用。     

Polymorphisms in the DNA repair gene XRCC1 and susceptibility to alcoholic liver cirrhosis in older Southeastern Brazilians

The population of Southeastern Brazil has a very high mortality rate from liver cirrhosis, a disease that is considered an irreversible pre-malignant condition. This is largely due to the high prevalence of alcohol abuse in the region. Chronic alcohol consumption is associated with the production of free radical intermediates that can cause several DNA lesions. Reduced repair of these DNA lesions would, therefore, constitute a significant risk factor for liver cirrhosis and subsequent cancer. Recently, a number of polymorphisms in several DNA repair genes have been discovered, and it is possible that these polymorphisms may affect DNA repair capacity and thus modulate susceptibility to the disease. In this study, we tested the hypothesis that polymorphisms in the DNA repair gene XRCC1 are associated with increased risk of liver cirrhosis in Southeastern Brazilians. We conducted a pilot case-control study of 97 liver cirrhosis cases and 96 controls (matched for age, sex, and ethnicity) to investigate the role of two allelic variants coding for amino acid changes in the XRCC1 gene (the Arg194Trp and the Arg399Gln polymorphisms). Overall, we observed a 1.8-fold increase in the relative risk of liver cirrhosis associated with the 399Gln allele (either the heterozygous Arg/Gln or the homozygous Gln/Gln genotypes). The adjusted odds ratio (OR) was 1.82 (95% confidence limit (CL) 1.10–3.30). The relative risk appears to be highest among the Mestiso ethnic group (OR 2.60, 95% CL 0.92–7.34). There was a significant association between the 399Gln polymorphism and the risk of liver cirrhosis in older individuals over the age of 45 years (OR 2.70 (95% CL 1.14–6.48) compared to an OR of 1.24 (95% CL 0.55–2.78) for those under 45 years of age. No association was observed between the XRCC1 194Trp polymorphism and risk of liver cirrhosis. These preliminary results suggest that the XRCC1 399Gln polymorphism may be a significant risk modifier for alcoholic liver cirrhosis and justifies additional studies in that direction.     

DNA repair gene XRCC2 and XRCC3 polymorphisms and susceptibility to cancers of the upper aerodigestive tract

Cigarette smoke can generate reactive oxygen species, which are capable of inducing double-strand breaks (DSBs) in DNA. Polymorphisms in XRCC2 and XRCC3 genes, involved in DSBs repair pathways, may alter an individual's susceptibility to smoking-related cancers. We investigated the effect of XRCC2 Arg(188)His and XRCC3 Thr(241)Met polymorphisms in cancer proneness in 121 oral/pharynx cancer cases, 129 larynx cancer cases and 172 noncancer controls, all Caucasian smokers. The XRCC2 His-allele was associated with a significantly increased risk of pharyngeal cancer (OR=2.9, 95% CI: 1.3-6.2). No significant associations were observed between the XRCC3 Thr(241)Met polymorphism and overall risk of developing UADT cancers. However, quite opposite to the expectations, a reduced risk of supraglottic cancer was found for carriers of the XRCC3 Met variant allele (OR=0.3, 95% CI: 0.2-0.7). These findings provide evidence for the view that polymorphisms in DNA repair genes may modify individual susceptibility to smoking-related cancers.     

XRCC1 polymorphisms and risk of nasopharyngeal carcinoma: a meta-analysis

Objective: Previous studies on the association between X-ray repair cross-complementing protein 1 (XRCC1) polymorphisms and nasopharyngeal carcinoma (NPC) risk showed inconsistent results. The aim of this study was to evaluate the effects of XRCC1 variants on NPC risk. Methods: A meta-analysis was performed with all eligible studies covering a total of 1,341 cases and 1,425 controls for the Arg194Trp polymorphism, 1,260 cases and 1,207 controls for the Arg280His polymorphism, and 1,644 cases and 1,678 controls for the Arg399Gln polymorphism. Results: No associations was found between Arg194Trp and Arg280His polymorphisms with NPC risk under all contrast models (co-dominant, dominant, and recessive models). However a deleterious effect of the 399Gln genotype was observed under the co-dominant model (Gln/Gln versus Arg/Arg, OR = 1.30, 95% CI : 1.01-1.69, P = 0.04). Under the recessive model (Gln/Gln versus Arg/Arg+Arg/Gln), the P value was marginally significant (OR = 1.28, 95% CI : 1.00-1.65, P = 0.05). However, the effect of the 399Gln genotype on NPC became non-significant after excluding one study from the meta-analysis because of departure from Hardy-Weinberg equilibrium. Conclusions: No associations was found between Arg194Trp and Arg280His polymorphisms with NPC risk, whereas the Arg399Gln genotype was associated with increased risk.     

DNA repair gene hOGG1 codon 326 and XRCC1 codon 399 polymorphisms and bladder cancer risk in a Japanese population

Background: Bladder cancer is the most common urologic malignancy in theUSA. Tobacco smoking generates oxidative DNA damage and inducesbladder cancer. Base excision repair (BER) is a very importantmechanism for repairing oxidative DNA damage. There are manyenzymes involved in BER. Human oxoguanine glycosylase 1 (hOGG1)and X-ray repair cross-complementing 1 (XRCC1) are enzyme genesof BER. Actually, the hOGG1 codon 326 polymorphism was associatedwith the risk of lung oesophagus and stomach cancer. On theother hand, among several XRCC1 gene polymorphisms, codon 399polymorphism was reported to reduce the risk of bladder cancerand raise the risk of lung cancer. Methods: We examined the association between the genetic polymorphismsof hOGG1 codon 326 and XRCC1 codon 399 and bladder cancer risk.In this study, we recruited 251 bladder cancer cases and 251healthy controls to evaluate the effect of hOGG1 codon 326 andXRCC1 codon 399 polymorphisms on bladder cancer. We detectedgenotypes by the polymerase chain reaction–restrictionfragment length polymorphism (PCR–RFLP) method. Results: The frequencies of the hOGG1 codon 326 genotypes Cys/Cys wassignificantly higher in the cases than in the controls. Adjustedodds ratio (OR) was 1.85 (95% CI: 1.12–3.03; p = 0.02)compared with Ser/Ser, and was 2.05 (95% CI: 1.36–3.08;p = 0.01) compared with Ser/Ser + Ser/Cys. In addition, whenevaluated with smoking status, the adjusted OR (Cys/Cys versusSer/Ser + Ser/Cys) ran up to 2.78 (95% CI: 1.39–5.60;p < 0.01) among non-smokers. For the XRCC1 polymorphism,the Gln/Gln of XRCC1 codon 399 genotype was statistically higherin the controls than in the cases though compared with Alg/Alg+ Alg/Gln. The adjusted OR was 0.45 (95% CI: 0.21–0.99;p = 0.05), and was lifted up to 0.37 (95% CI: 0.14–0.98;p = 0.05) among smokers. Conclusion: It is indicated that the hOGG1 codon 326 and XRCC1 codon 399polymorphisms are risk factors of bladder cancer.     

修复基因XRCC1 Arg194Trp位点多态性与肝癌易感性的关系

目的：探讨DNA损伤修复基因XRCC1多态与肝癌遗传易感性的关系。方法：本研究选取了130例肝癌患者及130例性别、年龄相匹配的正常对照者进行研究,采用限制性片段长度多态性方法,比较不同基因型与肝癌发病的关系。结果：变异型等位基因XRCC1 Arg/Trp及Trp/Trp的出现率在肝癌组和对照组中分别是27.69%和10.77%,（P〈0.05）;而野生基因型XRCC1 Arg/Arg出现率在肝癌组和对照组中分别是72.31和89.23%,（P〉0.05）。结论：XRCC1基因Arg194Trp位点单核苷酸多态在肝癌的发生过程中起着至关重要的作用。     

An updated meta-analysis between the association of XRCC1 Arg399Gln polymorphism and hepatocellular carcinoma risk

Background: Various studies have evaluated the relationship between X-ray repair cross-complementinggroup 1 (XRCC1) Arg399Gln polymorphism and hepatocellular carcinoma (HCC) risk, but the conclusionshave been inconsistent and underpowered. The purpose of this updated meta-analysis was to examine whetherXRCC1 Arg399Gln polymorphism confers susceptibility to HCC. Methods: Eligible studies extracted fromPubMed, Embase, Cochrane Library, VIP (chinese) and CNKI (chinese) up to November 2013 were included inthe study. Pooled odds ratio (OR) together with their 95% confidence interval (CI) were estimated to evaluateXRCC1 Arg399Gln polymorphism and HCC risk. Results: Finally, 21 studies with 4,170 cases and 5,030controls were involved in our meta-analysis. The results demonstrated that there was significant associationbetween Arg399Gln polymorphism and HCC risk under two contrast models in overall populations (AG vs GG:OR=1.265, 95%CI=1.036-1.545, p=0.021; AA+AG vs GG: OR=1.240, 95%CI=1.021-1.506, p=0.030). In subgroupanalyses, significant association was found in Asians (A vs G: OR=1.175, 95%CI=1.013-1.362, p=0.033; AG vsGG: OR=1.317, 95%CI=1.070-1.622, p=0.009; AA+AG vs GG: OR=1.289, 95%CI=1.055-1.575, p=0.013) andCaucasians (A vs G: OR=0.591, 95%CI=0.361-0.966, p=0.036; AA+AG vs GG: OR=0.468, 95%CI=0.234-0.934,p=0.031). Conclusions: The results suggest that XRCC1 Arg399Gln polymorphism may increase HCC riskespecially among Asians. However, XRCC1 Arg399Gln polymorphism might act as a protective role againstHCC among Caucasians.