title: Association between XRCC5, 6 and 7 gene polymorphisms and the risk of breast cancer: a HuGE review and meta-analysis.
abstract: 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 of breast cancer. The aim of this Human Genome Epidemiology (HuGE) review and meta-analysis was to investigate associations between XRCC5, XRCC6 and XRCC7 genetic polymorphisms in the NHEJ pathway and breast cancer risk.
  
  
  METHODS
  Studies focusing on the relationship between genetic polymorphisms in XRCC5, XRCC6 and 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. The odds 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 and 3,060 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 polymorphisms and the risk of breast cancer.
  
  
  CONCLUSIONS
  This meta-analysis suggests that the rs3835 G>A and rs828907 G>T in XRCC5 gene, rs6002421 (A>G), rs132788 (G>T) and rs132793 (G>A) in XRCC6 gene might be risk factors for breast cancer, while the rs132788 (G>T) and rs6002421 (A>G) in XRCC6 gene might be protective.
authors.affiliation: Department of Laboratory Medicine, First Affiliated Hospital of China Medical University, Shenyang, China.
authors.forename: Li-Ping
authors.initials: LP
authors.lastname: Zhou
authors.forename: Hong
authors.initials: H
authors.lastname: Luan
authors.forename: Xi-Hua
authors.initials: XH
authors.lastname: Dong
authors.forename: Guo-Jiang
authors.initials: GJ
authors.lastname: Jin
authors.forename: Dong-Liang
authors.initials: DL
authors.lastname: Man
authors.forename: Hong
authors.initials: H
authors.lastname: Shang
mesh_terms: D034961:Antigens, Nuclear / Q000235:genetics*; D044466:Asian People / Q000235:genetics*; D001943:Breast Neoplasms / Q000209:etiology*; D016022:Case-Control Studies; D002681:China / Q000453:epidemiology; D004265:DNA Helicases / Q000235:genetics*; D051747:DNA-Activated Protein Kinase / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D000072200:Ku Autoantigen; D015201:Meta-Analysis as Topic; D009687:Nuclear Proteins / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012307:Risk Factors
chemical_list: D034961:Antigens, Nuclear; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D051747:DNA-Activated Protein Kinase; C497263:PRKDC protein, human; D004265:DNA Helicases; C106893:XRCC5 protein, human; C000606509:Xrcc6 protein, human; D000072200:Ku Autoantigen