title: Association of X-ray repair cross complementing group 1 Arg399Gln polymorphisms with the risk of squamous cell carcinoma of the head and neck: evidence from an updated meta-analysis.
abstract: BACKGROUND
  Epidemiologic studies have reported the association of X-ray repair cross-complementary group 1 (XRCC1) Arg399Gln polymorphisms with susceptibility to squamous cell carcinoma of the head and neck (HNSCC). However, the results were conflictive rather than conclusive. The purpose of this study was to clarify the association of XRCC1 Arg399Gln variants with HNSCC risk.
  
  
  METHODS
  Systematic searches were performed through the search engines of PubMed, Elsevier, Science Direct, CNKI and Chinese Biomedical Literature Database. Summary odds ratio (OR) with 95% confidence intervals (CI) was computed to estimate the strength association.
  
  
  RESULTS
  Overall, we did not observe any association of XRCC1 Arg399Gln polymorphisms with HNSCC risk in total population (OR = 0.95, 95% CI: 0.76-1.19 for Gln/Gln vs. Arg/Arg, OR = 1.05, 95% CI: 0.92-1.20 for Arg/Gln vs. Arg/Arg, and OR = 1.03, 95% CI: 0.90-1.18 for Gln/Gln+Arg/Gln vs. Arg/Arg) based on 18 studies including 3917 cases and 4560 controls. In subgroup analyses, we observed an increased risk of XRCC1 399 Arg/Gln genotype for HNSCC in Caucasians (OR = 1.20, 95% CI: 1.00-1.44) and Gln/Gln genotype for larynx squamous cell carcinoma (OR = 1.63, 95% CI: 1.10-2.40). We did not observe any association between XRCC1 Arg399Gln variants and HNSCC risk in additional subgroup analyses.
  
  
  CONCLUSIONS
  The results from this present meta-analysis suggest that XRCC1 Arg399Gln variants may contribute to HNSCC risk among Caucasians and to the risk of larynx squamous cell carcinoma. Further, well-designed studies with larger sample sizes are required to verify our findings.
authors.affiliation: Henan Center for Disease Control and Prevention, Zhengzhou, China ; Department of Occupational Health and Occupational Medicine, School of Public Health and Tropic Medicine, Southern Medical University, Guangzhou, China.
authors.forename: Yadong
authors.initials: Y
authors.lastname: Wang
authors.forename: Xinwei
authors.initials: X
authors.lastname: Chu
authors.forename: Xiaojing
authors.initials: X
authors.lastname: Meng
authors.forename: Fei
authors.initials: F
authors.lastname: Zou
mesh_terms: D002294:Carcinoma, Squamous Cell / Q000209:etiology*; D016022:Case-Control Studies; D004268:DNA-Binding Proteins / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D006258:Head and Neck Neoplasms / Q000209:etiology*; D006801:Humans; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D011379:Prognosis; D012307:Risk Factors; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D004268:DNA-Binding Proteins; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human