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.     

Association Between Polymorphisms of XRCC1 Arg399Gln and XPD Lys751Gln Genes and Prognosis of Colorectal Cancer in a Chinese Population

We conducted this study to detect associations between XRCC1 Arg399Gln and XPD Lys751Gln genotypesand survival of colorectal cancer patients treated with 5-FU/oxalipatin chemotherapy. We included 289 Chinesepatients with advanced colorectal cancer, who had received 5-FU/oxalipatin chemotherapy as first-line treatmentfrom January 2005 to January 2007. All patients were followed up till Nov. 2011. Genotyping for XRCC1Arg399Gln and XPD Lys751Gln polymorphisms was based upon duplex polymerase-chain-reaction with thePCR-RFLP method. In our study, we found the XRCC1 399 Gln/Gln genotype to confer significantly higherrates of response to chemotherapy when compared to the Arg/Arg genotype [OR (95% CI)= 2.56(1.57-2.55)].patients with the XPD 751 Gln/Gln genotype had significantly higher rates of response to chemotherapy [OR(95% CI)= 1.54(0.87-2.65)] and those with the XRCC1 399 Gln/Gln genotype had a longer average survivaltime and significantly lower risk of death than did those with the Arg/Arg genotype [HR (95% CI)= 0.66(0.36-0.95)]. Similarly, those carrying the XPD 751Gln/Gln genotype had 0.51-fold the risk of death of those with XPD751Lys/Lys [HR (95% CI)= 0.51(0.33 -0.94)]. In conclusion, it is suggested that the XRCC1 Arg399Gln and XPDLys751Gln polymorphisms should be routinely assessed to determine colorectal patients who are more likely tobenefit from 5-FU/oxalipatin chemotherapy.     

Associations Between XRCC1 Arg399Gln,Arg194Trp,and Arg280His Polymorphisms and Risk of Differentiated Thyroid Carcinoma: A Meta-analysis

Background: Associations between Arg399Gln, Arg194Trp and Arg280His polymorphisms of the XRCC1 geneand risk of differentiated thyroid carcinoma (DTC) have been widely studied but the findings are contradictory.Methods: We performed a meta-analysis in the present study using STATA 11.0 software to clarify any associations.Electronic literature databases and reference lists of relevant articles revealed a total of 10, 6 and 6 publishedstudies for the Arg399Gln, Arg194Trp and Arg280His polymorphisms, respectively. Results: No significantassociations were observed between Arg399Gln and DTC risk in all genetic models within the overall andsubgroup meta-analyses, while the Trp/Trp vs Arg/Arg and recessive model of the Arg194Trp polymorphismwas associated with DTC susceptibility, and the dominant model of Arg280His polymorphism contributed toDTC susceptibility in Caucasians. Conclusions: Our meta-analysis suggests that XRCC1 Arg194Trp may be arisk factor for DTC development.     

XRCC1 Arg399Gln gene polymorphism and breast cancer risk: a meta-analysis based on case-control studies

Background: The Arg399Gln polymorphism in the XRCC1 DNA repair gene is likely to be involved with the development of breast cancer (BC). However, there have been inconsistent reports of association. The objective of this study was to systematically evaluate the published papers. Methods: We performed a meta-analysis of 44 published case-control studies fitting our eligibility criteria. These studies involved XRCC1 Arg399Gln polymorphisms in 20,841 BC cases and 22,688 controls in dominant (GlnGln+ArgGln vs. ArgArg), recessive (GlnGln vs. ArgGln+ArgArg), and co-dominant (GlnGln vs. ArgArg) inheritance models. Analyses of Asian, African and Caucasian ethnic subgroups was also conducted. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations. Results: Our overall analyses indicated Arg399Gln to be associated with a trend of increased BC risk when using recessive (OR=1.15, 95%CI: 1.05–1.27), and co-dominant models (OR=1.15, 95%CI: 1.04-1.27) to analyze the data. In ethnic subgroups, Arg399Gln significantly increased BC risk in Asians (OR=1.54, 95%CI: 1.18–2.01) when using recessive model analysis, in Africans (OR=1.30, 95%CI: 1.07–1.60) when using dominant model analysis, and in Asians (OR=1.50, 95%CI: 1.15–1.97) and Africans (OR=1.80, 95%CI: 1.08-3.02) when using the co-dominant model analysis. Conclusions: From our meta-analysis of data from 44 publications, we conclude that XRCC1 Arg399Gln allele is a risk factor for the development breast cancer, especially among Asian and African populations.     

XRCC1 Arg399Gln Gene Polymorphism and Hepatocellular Carcinoma Risk in the Chinese Han Population: A Meta-analysis

Purpose: Numerous studies have evaluated the association between XRCC1 Arg399Gln gene polymorphismand hepatocellular carcinoma risk in the Chinese Han population. However, the results have been inconsistent.We therefore here examined whether the XRCC1 Arg399Gln gene polymorphism confers hepatocellularcarcinoma risk by conducting a meta-analysis. Methods: PubMed, Google scholar and China National KnowledgeInfrastructure databases were searched for eligible articles in English and Chinese that were published beforeApril 2012. Results: 6 studies involving 1,246 patients with hepatocellular carcinoma and 1,953 controls wereincluded. The association between XRCC1 Arg399Gln gene polymorphism and hepatocellular carcinoma inthe Chinese Han population was significant under GG vs AA (OR = 1.48, 95% CI = 1.13 to 1.94). Limiting theanalysis to the studies with controls in the Hardy-Weinberg equilibrium, the results were persistent and robust.Conclusions: In the Chinese Han population, the XRCC1 Arg399Gln gene polymorphism is associated with anincreased hepatocellular carcinoma risk.     

XRCC1 Arg399Gln位点多态性和结直肠癌易感性关系的Meta分析

[目的]探讨X射线交叉互补修复基因1（X-ray repair cross-complementing group1,XRCC1）的399位点（Arg399Gln）多态性与结直肠癌（CRC）易感性的关系。[方法]检索中国生物医学数据库（CBM）、PubMed、Springer等数据库,获取有关XRCC1Arg399Gln多态性同结直肠癌易感性关系的病例对照研究并进行Meta分析,以病例组及对照组XRCC1Arg399Gln等位基因分布的比值比（OR）为效应指标,应用Meta分析软件Review Manager（version5.0.10）对各研究原始数据进行统计处理及异质性检验,计算合并OR值及其95%可信区间（95%CI）。[结果]纳入11项病例对照研究,共2287例结直肠癌患者和3485例对照,Meta分析结果显示,Gln/Gln vs.Arg/Arg OR=1.12,95%CI为0.76～1.65,Z=0.58,POR=0.56;Gln/Gln＋Arg/Gln vs.Arg/Arg OR=1.11,95%CI为0.85～1.44,Z=0.78,POR=0.43;Gln/Glnvs.Arg/Arg＋Arg/Gln OR=1.07,95%CI为0.79～1.46,Z=0.43,POR=0.67;Arg/Gln vs.Arg/Arg OR=1.14,95%CI为0.88～1.48,Z=1.02,POR=0.31。[结论]XRCC1Arg399Gln多态性与结直肠癌易感性之间无显著相关性。     

The XRCC1 Arg280His Gene Polymorphism and HepatocellularCarcinoma Risk: A Meta-analysis

Many studies have suggested that the XRCC1 Arg280His gene polymorphism might be involved in thedevelopment of hepatocellular carcinoma (HCC). However, the results have been inconsistent. In this study, theauthors performed a meta-analysis to assess the association between XRCC1 Arg280His and HCC susceptibility.Published literature from PubMed, EMBASE and CNKI Data was searched. Pooled odds ratios (ORs) and 95%confidence intervals (CIs) were calculated using fixed- or random- effects models when appropriate. Begg’stest was used to measure publication bias. A total of 7 case-control studies covering 1,448 HCC cases and 1,544controls were included. No significant variation in HCC risk was detected in any of the genetic models overall.In the stratified analysis, four studies with sample sizes over 300 produced similar results. The correspondingpooled ORs were not substantially altered after the exclusion of three studies deviating from Hardy-Weinbergequilibrium in the control group, which indicated reliability for our meta-analysis results.     

The XRCC1 Arg399Gln Gene Polymorphism and Risk of Colorectal Cancer: a Study in Kashmir

Background: The DNA repair gene XRCC1 Arg399Gln gene polymorphism has been found to be implicatedin the development of various cancers, including colorectal cancer (CRC), in different populations. We aimedto determine any association of this polymorphism with the risk of CRC in Kashmir. Materials and Methods:A total of 120 confirmed cases of CRC and 146 healthy cancer free controls from the Kashmiri population wereincluded in this study. Genotyping was carried out by the polymerase chain reaction- restriction fragment lengthpolymorphism (PCR-RFLP) method. Results: Genotype frequencies of XRCC1 Arg399Gln observed in controlswere 34.2%, 42.5% and 23.3% for GG (Arg/Arg), GA (Arg/Gln), AA( Gln/Gln), respectively, and 28.3%, 66.7%and 5% in cases, with an odds ratio (OR)=5.7 and 95% confidence interval (CI) =2.3-14.1 (p=0.0001). No significantassociation of Arg399Gln SNP with any clinicopathological parameters of CRC was found. Conclusions: Wefound the protective role of 399Gln allele against risk to the development of CRC. The XRCC1 heterozygotestatus appears to be a strong risk factor for CRC development in the Kashmiri population.     

Gene Polymorphism of XRCC1 Arg399Gln and Cervical Carcinoma Susceptibility in Asians: A Meta-analysis Based on 1,759 Cases and 2,497 Controls

Many epidemiological studies in Asian populations have investigated associations between the Arg399Glngene polymorphism of X-ray repair cross complementing gene 1 (XRCC1) and risk of cervical carcinoma, butno conclusions have been available because of controversial results. Therefore a meta-analysis was conducted forclarification. Relevant studies were identified by searching the Pubmed, Embase, the Web of Science, CochraneCollaboration’s database, Chinese National Knowledge Infrastructure (CNKI), Wanfang database and ChinaBiological Medicinse (CBM) until September, 2012. A total of eight studies were included in the present metaanalysis,which described 1,759 cervical carcinoma cases and 2,497 controls. Odds ratios (ORs) and corresponding95% confidence intervals (95%CIs) as effect size were calculated by fixed-effect or random-effect models.The overall results indicated that the XRCC1-399G/A polymorphism was marginally associated with cervicalcarcinoma in Asians: OR (95%CI): 1.16 (1.07, 1.26) in the G/A vs G/G inheritance model, 1.24 (0.87, 1.76)inA/A vs G/G inheritance model, 1.13 (1.01, 1.27) in the dominant inheritance model and 1.18 (0.94, 1.47) in therecessive inheritance model. Subgroup analyses on sample size showed no significant correlation in the smallsamplesize group but the large-sample size group was consistent with the outcomes of overall meta-analysis.In the subgroup analysis by regions, we only found significant association under the G/A vs G/G inheritancemodel in the Chinese population. For the non-Chinese populations, no correlation was detected in any geneticinheritance model. In the Asian populations, XRCC1-399G/A gene polymorphism was implied to be associatedwith cervical carcinoma.     

X-Ray Repair Cross-Complementing Group 1(XRCC1) Genetic Polymorphisms and Thyroid Carcinoma Risk: a Meta-Analysis

A number of studies have been conducted to explore the association of XRCC1 polymorphisms with thyroidcancer risk, but the results have been inconsistent. Thus we performed the present meta-analysis to clarify thisissue based on all of the evidence available to date. Relevant studies were retrieved by searching PubMed andstatistical analysis conducted using Stata software. Nine studies were included in this meta-analysis (1,620 casesand 3,557 controls). There were 6 studies (932 cases and 2,270 controls) of the Arg194Trp polymorphism, 7 studies(1432 cases and 3356 controls) of the Arg280His polymorphism and 9 studies (1,620 cases and 3,557 controls) forthe Arg399Gln polymorphism. No association of XRCC1 Arg194Trp, Arg280His and Arg399Gln polymorphismwith thyroid cancer risk was observed in the overall analysis. However, subgroup analysis revealed: 1) anelevated risk in aa vs AA analysis (OR=2.03, 95%CI= 1.24-3.31) and recessive genetic model analysis (OR=1.93,95%CI= 1.20-3.08) in the larger sample size trials for XRCC1 Arg194Trp polymorphism; 2) a decreased thyroidcancer risk on subgroup analysis based on ethnicity in Aa vs AA analysis (OR=0.84, 95%CI= 0.72-0.98) and ina dominant genetic model (OR=0.84, 95%CI= 0.72-0.97) in Caucasian populations for the XRCC1 Arg399Glnpolymorphism; 3) a decreased thyroid cancer risk on subgroup analysis based on design type in Aa vs AA analysis(OR=0.72, 95% CI= 0.54-0.97) among the PCC trials for the Arg399Gln polymorphism. Our results suggest thatthe XRCC1 Arg399Gln polymorphism may be associated with decreased thyroid cancer risk among Caucasiansand XRCC1 Arg194Trp may be associated with a tendency for increased thyroid cancer risk in the two largersample size trials.     

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.     

Association between the XRCC3 Thr241Met Polymorphism and Risk of Colorectal Cancer: a Meta Analysis of 5,193 Cases and 6,645 Controls

Background: Many studies have reported associations of the X-ray repair cross-complementing group 3(XRCC3) Thr241Met polymorphism with colorectal cancer (CRC) risk, but the results remained controversial.Hence, we performed the present meta-analysis with different inheritance models. Materials and Methods:We searched the PubMed and Google scholar databases for studies relating to associations between XRCC3Thr241Met polymorphism and risk of CRC. 16 studies with 5,193 cases and 6,645 controls were finally includedinto the meta-analysis. Results: We found that the XRCC3 Thr241Met polymorphism was associated withincreased CRC risk only under a dominant genetic model (CC+CT vs. TT: OR 0.575, 95%CI 0.498-1.665, p<0.001,Pheterogeneity =0.00, I2=83%). There was a significant association between XRCC3 Thr241Met polymorphism andCRC risk in Caucasian in the overall 8 studies under only in the heterozygote genetic model (CT vs. TT: OR=0.929,95%CI =0.806-1.070, P=0.308, Pheterogeneity =0.002, I2=57%). Four studies evaluated the XRCC3 Thr241Metpolymorphism and CRC risk in Asians. Two genetic models of the XRCC3 polymorphism were significantlycorrelated with increasing risk in Asians (dominant model: CC+CT vs. TT: OR= 0.609, 95%CI=411-0.902,P=0.013, Pheterogeneity =0.54, I2=0.00%; Allele model: C vs. T: OR=0.708, 95 %=CI 0.605-0.829, p=0.000, Pheterogeneity =0.000, I2=92%). The sensitivity analysis suggested stability of this meta-analysis and no publication bias wasdetected. Conclusions: In conclusion, this meta-analysis indicates that XRCC3 Thr241Met shows an increasedCRC risk, particularly in Asians rather than Caucasians.     

XRCC1基因Arg399Gln多态性与中国人群神经胶质瘤易感性Meta分析

目的:探讨XRCC1基因Arg399Gln (G/A)多态性与中国人群神经胶质瘤易感性的关系.方法:计算机检索Pubmed、EMBASE、中国知网、万方期刊、维普等中英文数据库,检索2014年10月之前公开发表的相关文献,对符合标准的文献采用NOS量表评价文献质量,应用RevMan5.1软件进行Meta分析.结果:共纳入9篇与XRCC1基因Arg399Gln多态性与神经胶质瘤易感性相关的病例对照研究,包括7 131例患者,其中病例组3 428例,对照组3 703例,NOS评分≥6分为高质量文献,仅2项研究质量评分＜6.Meta分析结果显示携带A等位基因可增加中国人群神经胶质瘤的患病风险(OR=1.20,95％CI:1.04～1.38,P=0.01).结论:中国人群中XRCC1基因Arg399Gln (G/A)多态性与神经胶质瘤的易感性存在相关性.     

The Codon 399 Arg/Gln XRCC1 Polymorphism is Associated with Lung Cancer in Indians

Background: The XRCC1 (X-ray repair cross complimenting group-I) gene in BER (base excision repair)pathway is essential for DNA repair process. Polymorphisms in this gene are associated with variations in the repairefficiency which might predispose individuals to development of various cancers. Two variants of XRCC1gene(at codon 399), Gln/Gln and Arg/Gln, have been shown to be related to lowered DNA repair capacity andincreased genomic instability in multiple studies. Hence our investigation focused on genotyping these variantsto correlate with other multiple risk factors in lung cancer (NSCLC) patients since we hypothesized that thesevariants of the XRCC1 gene might influence disease susceptibility. Materials and Methods: We examined thefrequency of the polymorphism in one hundred cases and an almost equal number of controls after recordingtheir demographics with a structured questionnaire. Genomic DNA from blood samples was extracted for PCRstudies, followed by RFLP to determine the variants. The significance of the data was statistically analyzed.Results: The three genotypes in cases and controls were Arg/Arg (40% and 54.45%); Gln/Gln (19% and 9.90%),and Arg/Gln (41.0% and 35.64%) respectively. Among these 3 genotypes, we found Gln/Gln and Arg/Gln toshow association with lung cancer. Correlating these genotypes with several parameters, we also found that thesetwo variants were associated with risk in males (p<0.05) and with smoking habits (p<0.05). In females Arg/Glngenotype showed association with stage of the disease (p=0.04). This is the first report in South Indian scenariowhere Arg399Gln genotypes were found to be associated with stage of the disease in females. Conclusions: Itis concluded that XRCC1 genotypes Gln/Gln and Arg/Gln may influence cancer susceptibility in patients withsmoking habits and these functional SNPs in XRCC1 gene may act as attractive candidate biomarkers in lungcancer for diagnosis and prognosis.     

Association Between XRCC5, 6 and 7 Gene Polymorphisms and the Risk of Breast Cancer: A HuGE Review and Meta-analysis

Objective: Non-homologous end joining (NHEJ) is a pathway for repairing DNA double-strand breaks.Recent publications indicated that XRCC5, XRCC6 and XRCC7 genes may participate in the pathogenesis ofbreast cancer. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis was to investigateassociations between XRCC5, XRCC6 and XRCC7 genetic polymorphisms in the NHEJ pathway and breastcancer risk. Methods: Studies focusing on the relationship between genetic polymorphisms in XRCC5, XRCC6and XRCC7 genes and susceptibility to breast cancer were selected from the Pubmed, Cochrane library, Embase,Web of Science, Springerlink, CNKI and CBM databases. Data were extracted by two independent reviewers.The meta-analysis was performed with Review Manager Version 5.1.6 and STATA Version 12.0 software. Theodds ratio (OR) with 95% confidence interval (95%CI) was calculated based on the extracted data. Results:According to the inclusion criteria, we final included seven studies with a total of 2,864 breast cancer cases and3,060 healthy controls. Meta-analysis results showed that rs3835 (G>A) and rs828907 (G>T) in XRCC5 gene,and rs132793 (G>A) in XRCC6 gene might increase the risk of breast cancer, while rs132788 G>T and rs6002421(A>G) might be protective factors. However, there was no relationship between XRCC7 genetic polymorphismsand the risk of breast cancer. Conclusion: This meta-analysis suggests that the rs3835 G>A and rs828907 G>Tin XRCC5 gene, rs6002421 (A>G), rs132788 (G>T) and rs132793 (G>A) in XRCC6 gene might be risk factorsfor breast cancer, while the rs132788 (G>T) and rs6002421 (A>G) in XRCC6 gene might be protective.     

XRCC1 Gene Polymorphism,Diet and Risk of Colorectal Cancer in Thailand

Background: Colorectal cancer (CRC) is one of the most common cancers worldwide. This study aimed to investigate the interaction between the presence of a polymorphism of the XRCC1 gene and known risk factors for colorectal cancer in Thailand. Materials and Methods: A hospital-based case-control study was conducted in Thailand. The participants were 230 histologically confirmed new cases and 230 controls matched by sex and age and recruited from the same hospital. Information about demographic characteristics, life style, anddietary habits was collected using structured interviews, and blood samples were taken which were used for the detection of a homozygous and heterozygous polymorphisms of XRCC1. Associations were assessed using multiple conditional logistic regression. Results: In the univariate analysis, factors found to be significantly associated with an increased risk for CRC were the presence of the XRCC1 AA homozygote (OR= 4.95; 95% CI: 1.99-12.3), a first degree family history of cancer (OR= 1.74; 95% CI: 1.18-2.58), and a high frequency ofpork consumption (OR= 1.49; 95% CI: 1.00-2.21). Intakes of fish fruit and vegetables appeared to be protective factors, but the associations were not statistically significant. In the multivariate analysis only the XRCC1 AAhomozygote polymorphism and a family history of cancer emerged as risk factors (OR= 4.96; 95% CI: 1.90-12.95 and OR=1.80; 95% CI: 1.18-2.72, respectively). Conclusions: While the XRCC1 AA homozygote and a family history of cancer were found to be associated with an increased risk of CRC, none of the dietary intake variables were clearly identified as risk or protective factors. There is a need for further research to determine the reasons for this.     

XRCC1基因Arg399Gln多态与胃癌临床病理因素的关系

背景与目的：DNA修复基因XRCC1参与DNA损伤的碱基切除修复途径（BER），其Arg399Gln多态可以改变蛋白产物的DNA修复效能．本研究探讨XRCC1基因Arg399Gln多态与胃癌临床病理因素的关联性。方法：采用聚合酶链反应PCR-变性高效液相色谱分析（denaturing high performance liquid chromatography，DHPLC）方法对102例胃癌患者进行XRCC1基因Arg399Gln多态的基因型分析，比较基因型分布与胃癌组织临床病理特征之间的关系。结果：XRCC1基因Arg399Gln多态的Arg／Arg（GG），Arg／Gin（G→A）及Gin／Gin（AA）基因型在病例组中的分布频率分别为46（45．1％），48（47．1％），8（7．8％）；含至少一个399Gln的基因型患胃癌的年龄明显要小（P=0．07）；Arg399Gln多态性与胃癌的病理类型、肿瘤部位、组织分级、浸润深度及淋巴结转移、临床分期间没有显著关系（P〉0．05）。结论：XRCC1基因399Gln等位基因可能是胃癌早年发病的危险因素之一；但不是判断胃癌侵袭相关的生物学行为的预测指标。这些结果还需要大样本量的胃癌分子流行病学研究加以验证。     

Association Between the XRCC3 Thr241Met Polymorphism and Cervical Cancer Risk: a Meta-analysis

Background: Numerous epidemiological studies have been conducted to evaluate the association betweenvariants of the DNA repair gene XRCC3 and cancer risk. Here we focused on one XRCC3 polymorphism anddevelopment of cervical cancer, performing a meta-analysis. Methods: The pooled association between theXRCC3 Thr241Met polymorphism and cervical cancer risk was assessed by odds ratios (ORs) and their 95%confidence intervals (95%CIs). Results: A total of 5 case-control studies met the inclusion criteria. The pooledORs for the total included studies showed no association among homozygotes TT vs. CC: OR=1.93, 95%CI=0.68-5.49, P=0.22; dominant model TT+TC vs. CC: OR=1.37, 95%CI=0.90-2.06, P=0.14; and recessive model TT vs.TC+CC: OR=1.76, 95%CI=0.68-4.55, P=0.25, but might be a slight risk factor for cervical cancer in heterozygotecontrast TT vs. CT: OR= 1.33, 95%CI=1.04-1.71, P=0.02. In subgroup analysis, significant associations werefound for Asians under all genetic models. Conclusions: Our meta-analysis suggested the XRCC3 Thr241Metpolymorphism might not act as a cervical cancer risk factor overall. However, in subgroup analysis, a significantassociation was found in Asians under all genetic models. The association should be studied with a larger, stratifiedpopulation, especially for Asians.     

Association between the XRCC1 Arg194Trp Polymorphism and Glioma Risk: an Updated Meta-analysis

Gliomas are the most common type of primary brain tumors. The XRCC1 Arg194Trp variant affects the proliferating cell nuclear antigen( PCNA) binding region, which suggests that this mutation may contribute to gliomagenesis and a number of articles have examine the association between XRCC1 Arg194Trp and the susceptibility to glioma. However, the results were conflicting. Test of heterogeneity, sensitivity analysis, metaanalysis, and assessment of publication bias were all performed in our present meta-analysis, covering a total of5,407 patients and 7,715 healthy persons. In the overall analysis the XRCC1 Arg194Trp polymorphism showed a significant association with glioma susceptibility in a recessive mode l(for TrpTrp vs ArgArg+ArgTrp: OR=1.918,95%CI=1.575-2.336, I2=2.3%). In addition, analysis of subgroups presented an increased risk in Asians and populations-based on hospitals. The results suggested that the XRCC1 Arg194Trp polymorphism is a genetic risk factor for glioma, especially in Asian population. To further evaluate gene-gene and gene-environment interactions on XRCC1 polymorphisms and glioma risk, thousands of subjects and tissue-specific biochemical characterizations are required.     

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。