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

Association of XRCC1 p. Arg194Trp gene polymorphism with the risk of hepatocellular carcinoma in HCV Egyptian population: A pilot case-control study

Background: Hepatocellular carcinoma (HCC) is the most common and fatal primary liver cancer. Genetic variants of DNA repair systems can reduce DNA repair capability and increase HCC risk. Objectives: This study aimed to examine, in Egyptian hepatitis C virus (HCV) patients, the relationship between the X-ray repair cross-complementing group 1 (XRCC1) rs1799782 single nucleotide polymorphism (SNP) and HCC susceptibility. Methods: We included 100 adult HCV-positive patients with HCC and 100 adult HCV-positive patients with liver cirrhosis as pathological controls. XRCC1 rs1799782 SNP genotyping was done in both groups using quantitative real-time PCR (qPCR). The distribution of genotypes in patients and controls was compared using several inheritance models. Results: We found that the CT genotype, when analyzed under both the co-dominant (OR (95 % CI): 2.147 (1.184-3.893), p = .012) and the over-dominant (OR (95 % CI): 2.055 (1.153-3.660), p = .015) models, as well as the combined CT and TT genotypes under the dominant model (OR (95 % CI) of 1.991 (1.133-3.497), p = .017), were associated with increased susceptibility to HCC. The frequency of the T allele was higher among HCC participants (32%) compared to those with cirrhosis (23.5%) and carrying the T allele increased the risk of HCC by 1.532 times, however, these associations did not reach statistical significance (p-values >0.05). Moreover, the variant T allele was associated with worse clinical manifestations and laboratory results among the HCC group, but AFP levels were not affected significantly. Conclusions: Egyptians with XRCC1 rs1799782 SNP may have a higher risk of HCV-related HCC. More extensive multi-center prospective investigations must confirm this association.

Genetic and biochemical studies of hepatic carcinoma in the Egyptian population

Background

Hepatocellular carcinoma (HCC), a deadly malignancy of the liver, is considered the third leading reason behind cancer deaths. It is more frequent in men than in women of ages above 50. Liver disease, leading to liver cirrhosis (LC), is mostly caused by alcoholism abuse, reaction diseases of the liver, or viral hepatitis B or C infection. Interleukin-6 (IL-6) is considered an effective pro-inflammatory cytokine, which plays a crucial role in the host defense mechanism. Its level is higher in HCC patients than in LC cases, indicating that tumor cells increase the production of cytokines. The X-ray repair cross-complementing group 1 (XRCC1) gene is a major DNA repair gene. It acts as a scaffold of various activities that are concerned in the repairing method by interacting with components of base excision repair. This study aims to measure the serum concentrations of IL6 and C-reactive protein (CRP) and investigate whether XRCC1 Arg194Trp and Arg399Gln polymorphisms are related to HCC disease.

Materials and Methods

Whole-blood DNA was extracted from 123 HCC patients and 123 healthy volunteers. Tetra-primer amplification refractory mutation system was performed in the detection of XRCC1 Arg399Gln and Arg194Trp polymorphisms.

Results

Serum concentration levels of IL-6 and CRP are significantly higher in patients with HCC than in control subjects. The allelic and genotype frequency distributions of XRCC1 (Arg399Gln and Arg194Trp) are significantly increased in HCC cases compared to healthy volunteers.

Conclusion

Arg/Gln, Arg/Trp, Gln/Gln, and Trp/Trp genotypes are associated with higher risk HCC than the Arg/Arg genotype.

Liver Cirrhosis in Chronic Hepatitis B Patients Is Associated with Genetic Variations in DNA Repair Pathway Genes

Simple Summary

As DNA repair enzymes affect dynamics of liver damage and are involved in HBV viral replication, this study focused on the role of genetic variations within genes representing key DNA-repair pathways in HBV-induced liver cirrhosis. The obtained results have demonstrated that SNPs within XRCC1, ERCC2 genes may confer susceptibility to liver cirrhosis in chronic hepatitis B patients.

Abstract

Liver cirrhosis (LC), contributing to more than 1 million of deaths annually, is a major healthcare concern worldwide. Hepatitis B virus (HBV) is a major LC etiological factor, and 15% of patients with chronic HBV infection (CHB) develop LC within 5 years. Recently, novel host genetic determinants were shown to influence HBV lifecycle and CHB course. DNA repair enzymes can affect dynamics of liver damage and are involved in HBV covalently closed circular DNA (cccDNA) formation, an essential step for viral replication. This study aimed to evaluate the possible role of genes representing key DNA-repair pathways in HBV-induced liver damage. MALDI-TOF MS genotyping platform was applied to evaluate variations within XRCC1, XRCC4, ERCC2, ERCC5, RAD52, Mre11, and NBN genes. Apart from older age (p < 0.001), female sex (p = 0.021), portal hypertension (p < 0.001), thrombocytopenia (p < 0.001), high HBV DNA (p = 0.001), and high aspartate aminotransferase (AST) (p < 0.001), we found that G allele at rs238406 (ERCC2, p = 0.025), T allele at rs25487 (XRCC1, p = 0.012), rs13181 GG genotype (ERCC2, p = 0.034), and C allele at rs2735383 (NBN, p = 0.042) were also LC risk factors. The multivariate logistic regression model showed that rs25487 CC (p = 0.005) and rs238406 TT (p = 0.027) were independently associated with lower risk of LC. This study provides evidence for the impact of functional and potentially functional variations in key DNA-repair genes XRCC1 and ERCC2 in HBV-induced liver damage in a Caucasian population.

Associations between three XRCC1 polymorphisms and hepatocellular carcinoma risk: A meta-analysis of case-control studies

Conflicting results have been obtained regarding the association between X-ray repair cross complementation group 1 (XRCC1) and susceptibility to hepatocellular carcinoma (HCC). In this study, associations between HCC and three polymorphisms (Arg194Trp, Arg280His, and Arg399Gln) were evaluated using a meta-analysis approach. PubMed, Web of Science, Cochrane Library, the Chinese National Knowledge Infrastructure, and the Wanfang standard database were systematically searched to identify all relevant case-control studies published through March 2018. A total of 32 case-control studies, including 13 that evaluated Arg194Trp, 14 that evaluated Arg280His, and 26 that evaluated Arg399Gln, were analyzed. In the entire study population, XRCC1 Arg399Gln was significantly associated not only with overall risk of HCC (homozygous model, OR = 1.61, 95% CI: 1.40–1.85, P < 0.05; recessive model, OR = 1.40, 95% CI: 1.23–1.59, P < 0.05) but also with the risk of HCC in Chinese patients (homozygous model, OR = 1.78, 95% CI: 1.53–2.08, P < 0.05; recessive model, OR = 1.47, 95% CI: 1.27–1.70, P < 0.05). Limiting the analysis to studies demonstrating Hardy–Weinberg equilibrium (HWE), the results were consistent and robust. Similarly, a significant association between XRCC1 Arg399Gln and HCC risk was found in healthy controls in the general population but not in hospital controls. Trial sequential analysis (TSA), false-positive report probabilities (FPRP), and combined genotype analysis revealed that XRCC1 Arg399Gln is mainly associated with susceptibility to liver cancer. However, there was no association between Arg194Trp or Arg280His and the risk of HCC. These results, indicating that the Arg399Gln polymorphism of XRCC1 is associated with the risk of HCC in the Chinese population, provide a basis for the development of improved detection and treatment approaches.

Polymorphisms of base-excision repair genes and the hepatocarcinogenesis

AIM

To determine the possible association between polymorphisms of DNA repair genes, including XRCC1 Arg194Tryp, Arg280His, and Arg399Glu, APE1 Asp148Glu, and NEIL2 Arg257Leu, and the risk of developing hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC).

METHODS

A total of 264 subjects were recruited in this retrospective case-control study and were categorized into four groups: 88 control subjects (CR), 53 chronic hepatitis C patients (CHC), 36 liver cirrhotic patients (LC), and 87 HCC patients. The XRCC1 Arg194Tryp, Arg280His, and Arg399Glu polymorphisms were detected using PCR-RFLP, while real-time PCR was used to genotype APE1 Asp148Glu and NEIL2 Arg257Leu.

RESULTS

Our data revealed that, compared with the healthy controls, for those subjects with the XRCC1 Arg194Trp genotype, the risk of developing CHC, LC, and HCC was increased by 6.66- (odds ratio (OR) = 6.667; 95% confidence interval (CI) = 3.244-13.701; P > 0.01), 3.85- (OR = 3.852; 95% CI = 1.797-8.256; P > 0.01), and 2.14-fold (OR = 2.14; 95% CI = 1.13-4.06; P > 0.05), respectively. There was no association between the risk of HCC development and the XRCC1 Arg280His or XRCC1 Arg399Gln genotypes. Moreover, the analysis showed a lack of association between APE1 Asp148Glu and the risk of HCC development. The analysis of clinicopathological parameters showed that the HCC patients with the XRCC1 Arg280His polymorphism were 2.9 fold more likely to have hepatic lesions in both hepatic lobes (OR: 2.9; 95% CI: 1.15-7.29). Notably, in the HCC patients, the prevalence of the APE1 polymorphism in the males was four times higher than that in the females (OR = 4; 95% CI = 1.129-14.175; P > 0.05).

CONCLUSION

Our results indicate that the XRCC1 Arg194Trp polymorphism could be a risk factor for HCV-related HCC development in Egypt.

The X-ray Repair Cross-Complementing Group 1 Arg399Gln Genetic Polymorphism and Risk of Hepatocellular Carcinoma in an Iranian Population

BACKGROUND

The association between X-ray repair cross-complementing group 1 (XRCC1) Arg399Gln gene polymorphism and hepatocellular carcinoma (HCC) has been investigated in several populations. However, the findings are controversial. The aim of this study was to address the association between XRCC1 Arg399Gln polymorphism and HCC in an Iranian population.

METHODS

We have evaluated the association between XRCC1 Arg399Gln gene polymorphism and HCC in 151 Iranian individuals (50 patients with HCC and 101 healthy matched controls) using polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP) method.

RESULTS

Significant association was found for the XRCC1 A allele and HCC [OR = 1.93, 95% CI (1.16 - 3.25), P = 0.0099]. Also, genotype analysis by SNPStats online software showed a significant association between XRCC1 gene polymorphisms and HCC under co-dominant, dominant, and recessive genetic models.

CONCLUSION

Our study provides evidence that the XRCC1 Arg399Gln polymorphism may be associated with the risk of HCC development in Iranian population.

Association between Polymorphisms of X-Ray Repair Cross Complementing Group 1 Gene and Pancreatic Cancer Risk: a Systematic Review with Meta-Analysis

Emerging evidences have shown that common genetic polymorphisms in X-ray repair cross complementing group 1 (XRCC1) gene may be associated with the development of pancreatic cancer, but individually published studies and previous meta-analyses revealed inconclusive results. The aim of our study was to investigate the association between polymorphisms in XRCC1 gene and pancreatic cancer risk. We conducted a search of PubMed, Embase, the Cochrane Library and Web of Science databases. Odds ratios (ORs) with 95% confidence intervals (CIs) were determined as measures of the strength of association between polymorphisms of XRCC1 and pancreatic cancer risk. Sensitivity analysis and publication bias were evaluated. All analyses were undertaken using the STATA 13.0. A total of 10 studies were included in this systematic review. Five common functional single-nucleotide polymorphisms (SNPs) in XRCC1 gene were found, including Arg399Gln G > A (rs25487), Arg194Trp C > T (rs1799782), Arg280His G > A (rs25489), c.1517G > C, c.1471G > A. Results from our stratified analysis based on Hardy-Weinberg equilibrium (HWE) showed that there was a robust significant association between Arg280His polymorphism and pancreatic cancer risk (allelic model, OR 0.743, 95% CI 0.576-0.958, P = 0.022; heterozygous model, OR 0.701, 95% CI 0.525-0.936, P = 0.016; dominant model, OR 0.710, 95% CI 0.537-0.939, P = 0.016). We also found a statistically significant association between c.1517G > C polymorphism and pancreatic cancer risk (Allelic model, OR 1.252, 95% CI 1.064-1.473, P = 0.007). No significant results were obtained for Arg399Gln, Arg194Trp and c.1471G > A polymorphisms. The present meta-analysis suggested that Arg280His and c.1517G > C polymorphisms in XRCC1 gene were associated with pancreatic cancer risk.

XRCC1 Arg399Gln Gene Polymorphism and Hepatocellular Carcinoma Risk in the Italian Population

Background

The human X-ray repair cross-complementing protein 1 ( XRCC1) gene encodes for one of the major repair factors involved in base excision repair (BER), which is reported to be associated with the risk of several cancers. A few studies have explored the association between risk of hepatocellular carcinoma (HCC) and single-nucleotide polymorphisms (SNPs) in different DNA repair genes, with contradictory results. The purpose of this study was to evaluate the association between XRCC1 Arg399Gln polymorphism and susceptibility to HCC.

Methods

A total of 89 HCC patients and 99 randomly selected healthy controls were enrolled. Genotyping of XRCC1 rs25487 was performed by high-resolution melting analysis and Sanger sequencing.

Results

On univariate analysis, a statistically significant association was found between risk of HCC and XRCC1 399Arg/Gln genotype (odd ratio [OR] = 1.88; 95% CI, 1.04-3.43), which was confirmed after adjusting by sex (OR = 1.94; 95% CI, 1.04-3.63). Although not significant, Kaplan-Meier analysis showed a decreased median survival in Arg/Gln genotype carriers in comparison with Arg/Arg carriers.

Conclusions

To our knowledge, this is the first study reporting an association between BER SNP and HCC risk in a population of central-southern Italy.

The XRCC1 Arg194Trp polymorphism is significantly associated with lung adenocarcinoma: a case-control study in an Eastern European Caucasian group

DNA repair plays an important role in maintaining the integrity of the genome by repairing DNA damage induced by carcinogens. Certain genetic polymorphisms that occur in DNA-repair genes may affect the ability to repair DNA defects, and may represent a risk factor in carcinogenesis. The gene XRCC1 is involved in DNA repair. The purpose of our study was to investigate the association between XRCC1 Arg194Trp and Arg399Gln polymorphisms and the risk of lung cancer in a Romanian population. We recruited 222 healthy controls and 102 patients with lung cancer. Genotypes were determined by multiplex polymerase chain-reaction restriction fragment-length polymorphism. Statistical analysis (odds ratio, recessive model) revealed an increased risk for lung cancer for the homozygous 194Trp genotype (χ²=0.186, odds ratio 10.667, 95% confidence interval 1.309–86.933; P=0.007). Also, we found an association between the 194Trp allele and women with lung adenocarcinoma. In conclusion, the results of the study place the XRCC1 Arg194Trp polymorphism among independent risk factors for developing lung cancer.

XPD Lys751Gln and Asp312Asn polymorphisms and hepatocellular carcinoma susceptibility: A meta-analysis of 11 case-control studies in an Asian population

This meta-analysis was performed to evaluate the association between xeroderma pigmentosum complementary group D (XPD) Lys751Gln and Asp312Asn polymorphisms and susceptibility to hepatocellular carcinoma (HCC). PubMed, Embase, Google Scholar and the Chinese National Knowledge Infrastructure and the Chinese Biomedicine databases were systematically searched to identify relevant studies published up to June 1, 2014. Statistical analyses were performed using Stata version 12.0 software. A total of 11 case-control studies, comprising 2,852 cases and 2,936 controls, were included. The results of the meta-analysis revealed that a significant association between the risk of HCC and variant genotypes of the XPD Lys751Gln and Asp312Asn polymorphisms was evident in the homozygote comparison [Gln/Gln versus Lys/Lys: Odds ratio (OR), 1.831; 95% confidence interval (CI), 1.001-3.349], heterozygote comparison (Lys/Gln versus Lys/Lys: OR, 1.486; 95% CI, 1.044-2.114), dominant model (Gln/Gln + Lys/Gln versus Lys/Lys: OR, 1.540; 95% CI, 1.054-2.249) and allelic contrast (Gln-allele versus Lys-allele: OR, 1.453; 95% CI, 1.032-2.046) for the Lys751Gln polymorphism and the homozygote comparison for the Asp312Asn polymorphism (Asn/Asn versus Asp/Asp: OR, 1.352; 95% CI, 1.010-1.808). By contrast, no significant association was observed in the recessive model for the Lys751Gln polymorphism (Gln/Gln versus Lys/Gln + Lys/Lys: OR, 1.603; 95% CI, 0.924-2.779), or for the heterozygote comparison (Asn/Asp versus Asp/Asp: OR, 1.229; 95% CI, 0.857-1.762), dominant model (Asn/Asn + Asp/Asn versus Asp/Asp: OR, 1.249; 95% CI, 0.910-1.715), recessive model (Asn/Asn versus Asp/Asn + Asp/Asp: OR, 1.250; 95% CI, 0.940-1.663) or allelic contrast (Asn-allele versus Asp-allele: OR, 1.226; 95% CI, 0.965-1.557) for the Asp312Asn polymorphism. The present meta-analysis has indicated that the XPD Lys751Gln polymorphism could be a potential biomarker of HCC susceptibility and that the XPD Lys751Gln and Asp312Asn polymorphisms could be risk factors for HCC susceptibility in an Asian population; however, further large-scale and well-designed studies are required to reach a more precise and comprehensive conclusion.

XRCC1 R399Q polymorphism and colorectal cancer risk in the Chinese Han population: a meta-analysis

X-ray repair cross-complementing group 1 (XRCC1) plays a key role in DNA repair, genetic instability, and tumorigenesis. The XRCC1 R399Q polymorphism has been reported in some studies to influence the risk of colorectal cancer (CRC), though this remains controversial. We performed a meta-analysis to determine the association of XRCC1 R399Q polymorphisms with CRC risk in the Chinese Han population. A literature search was conducted using PubMed, EMBASE, and the China National Knowledge Infrastructure to identify eligible studies published before June 2014. The pooled odds ratio (OR) and corresponding 95% confidence interval (CI) were used to estimate the effect of XRCC1 R399Q polymorphisms on CRC risk. Eleven case-control studies with a total of 3194 CRC cases and 4472 controls were identified. No significant association between the XRCC1 R399Q polymorphism and CRC risk was observed in the Chinese Han population (Gln/Gln vs. Arg/Arg, OR = 1.26, 95% CI = 0.85-1.87, P OR = 0.242; Arg/Gln vs. Arg/Arg, OR = 0.95, 95% CI = 0.70-1.18, P OR = 0.651; dominant model, OR = 1.09, 95% CI = 0.86-1.38, P OR = 0.480; and recessive model, OR = 1.24, 95% CI = 0.91-1.70, P OR = 0.177). After excluding two studies that deviated from the Hardy-Weinberg equilibrium, there remained no significant association between XRCC1 R399Q and CRC risk. No publication bias was found using the funnel plot and Egger's test. Our meta-analysis results suggest that the XRCC1 R399Q polymorphism is not associated with increased risk of CRC in the Chinese Han population.

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-complementing group 1 (XRCC1) Arg399Gln polymorphism and hepatocellular carcinoma (HCC) risk, but the conclusions have been inconsistent and underpowered. The purpose of this updated meta-analysis was to examine whether XRCC1 Arg399Gln polymorphism confers susceptibility to HCC.

METHODS

Eligible studies extracted from PubMed, Embase, Cochrane Library, VIP (chinese) and CNKI (chinese) up to November 2013 were included in the study. Pooled odds ratio (OR) together with their 95% confidence interval (CI) were estimated to evaluate XRCC1 Arg399Gln polymorphism and HCC risk.

RESULTS

Finally, 21 studies with 4,170 cases and 5,030 controls were involved in our meta-analysis. The results demonstrated that there was significant association between 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 subgroup analyses, significant association was found in Asians (A vs G: OR=1.175, 95%CI=1.013-1.362, p=0.033; AG vs GG: 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) and Caucasians (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 risk especially among Asians. However, XRCC1 Arg399Gln polymorphism might act as a protective role against HCC among Caucasians.

Genetic polymorphisms of XRCC1 gene and susceptibility to hepatocellular carcinoma in Chinese population

Hepatocellular carcinoma (HCC) is a common cancer in the worldwide. Accumulated evidences indicate that genetic polymorphisms of human X-ray repair complementing group 1 gene (XRCC1) are associated with the susceptibility to HCC. This study aims to investigate the potential association between XRCC1 c.482C>T and c.1178G>A genetic polymorphisms and the susceptibility to HCC. A total of 1,069 Chinese Han subjects consisting of 530 HCC patients and 539 cancer-free controls were recruited in this case-control study. The created restriction site-polymerase chain reaction and directly DNA sequencing methods were utilized to analyze the genotyping of XRCC1 genetic polymorphisms. Our data suggested that the XRCC1 c.482C>T and c.1178G>A genetic polymorphisms were statistically associated with the increased risks of HCC [for c.482C>T, TT vs. CC: OR 2.05, 95% CI 1.26-3.32, P = 0.003; T vs. C: OR 1.26, 95% CI 1.04-1.51, P = 0.017; for c.1178G>A, AA vs. GG: OR 2.15, 95% CI 1.26-3.67, P = 0.004; A vs. G: OR 1.33, 95% CI 1.10-1.61, P = 0.004]. The allele-T and genotype-TT of c.482C>T and allele-A and genotype-AA of c.1178G>A genetic polymorphisms may enhance the susceptibility to HCC. Our findings indicate that the studied XRCC1 genetic polymorphisms may influence the risk of HCC in Chinese populations and might be used as molecular markers for assessing the risk of HCC.

Association between the XRCC1 Arg399Gln polymorphism and risk of cancer: evidence from 297 case-control studies

BACKGROUND

The Arg399Gln polymorphism in the X-ray cross-complementing group 1 (XRCC1) had been implicated in cancer susceptibility. The previous published data on the association between XRCC1 Arg399Gln polymorphism and cancer risk remained controversial.

METHODOLOGY/PRINCIPAL FINDINGS

To derive a more precise estimation of the association between the XRCC1 Arg399Gln polymorphism and overall cancer risk, we performed a meta-analysis of 297 case-control studies, in which a total of 93,941 cases and 121,480 controls were included. Overall, significantly increased cancer risk was observed in any genetic model (dominant model: odds ration [OR] = 1.04, 95% confidence interval [CI] = 1.01-1.07; recessive model: OR = 1.08, 95% CI = 1.03-1.13; additive model: OR = 1.09, 95% CI = 1.04-1.14) when all eligible studies were pooled into the meta-analysis. In further stratified and sensitivity analyses, significantly elevated hepatocellular and breast cancers risk were observed in Asians (dominant model: OR = 1.39, 95% CI = 1.06-1.84) and in Indians (dominant model: OR = 1.64, 95% CI = 1.31-2.04; recessive model: OR = 1.94, 95% CI = 1.09-3.47; additive model: OR = 2.06, 95% CI = 1.50-2.84), respectively.

CONCLUSIONS/SIGNIFICANCE

This meta-analysis suggests the participation of XRCC1 Arg399Gln is a genetic susceptibility for hepatocellular cancer in Asians and breast cancer in Indians. Moreover, our work also points out the importance of new studies for Arg399Gln association in some cancer types, such as glioma, gastric cancer, and oral cancer, where at least some of the covariates responsible for heterogeneity could be controlled, to obtain a more conclusive understanding about the function of the XRCC1 Arg399Gln polymorphism in cancer development.

XRCC1 Arg194Trp polymorphism is associated with oral cancer risk: evidence from a meta-analysis

Previous studies show that X-ray cross-complementing group 1 (XRCC1) Arg194Trp may result in variations in host's repair efficiency of DNA damage, and this repair deficit may eventually cause individual susceptibility to oral cancer. However, published data regarding the association between XRCC1 Arg194Trp polymorphism and oral cancer risk were contradictory. The aim of this study was to derive a more precise estimation of the association of XRCC1 Arg194Trp polymorphism with oral cancer by performing a meta-analysis. Odds ratios (ORs) and 95 % confidence intervals (95 % CIs) were used to assess the strength of the association. Finally, a meta-analysis of nine eligible studies including 1,281 cases and 1,966 controls was performed. Overall, there was a significant association between XRCC1 Arg194Trp polymorphism and oral cancer risk (for Trp versus Arg: OR = 1.41, 95 % CI 1.08-1.83, P = 0.01; for TrpTrp versus ArgArg: OR = 1.50, 95 % CI 1.00-2.30, P = 0.05; for TrpTrp/ArgTrp versus ArgArg: OR = 1.49, 95 % CI 1.14-1.94, P = 0.003). After excluding those studies containing patients with oral leukoplakia, there was still an obvious association between XRCC1 Arg194Trp polymorphism and oral cancer risk (for TrpTrp/ArgTrp versus ArgArg: OR = 1.40, 95 % CI 1.14-1.71, P = 0.001). Subgroup analysis by ethnicity suggested that there was an obvious association between XRCC1 Arg194Trp polymorphism and oral cancer risk in Asians under three genetic models. In conclusion, the results from this meta-analysis suggest that XRCC1 Arg194Trp polymorphism is associated with oral cancer risk, especially in Asians.