title: Association of functional polymorphisms of the XRCC4 gene with the risk of breast cancer: a meta-analysis.
abstract: OBJECTIVE
  X-ray cross-complementing group 4 (XRCC4) is a major repair gene for DNA double-strand breaks (DSB) in the non-homologous end-joining (NHEJ) pathway. Several potentially functional polymorphisms of the XRCC4 gene have been implicated in breast cancer risk, but individually published studies showed inconclusive results. The aim of this meta-analysis was to investigate the association between XRCC4 polymorphisms and the risk of breast cancer.
  
  
  METHODS
  The MEDLINE, EMBASE, Web of science and CBM databases were searched for all relevant articles published up to June 20, 2012. Potential associations were assessed with comparisons of the total mutation rate (TMR), complete mutation rate (CMR) and partial mutation rate (PMR) in cases and controls. Statistical analyses were performed using RevMan 5.1.6 and STATA 12.0 software.
  
  
  RESULTS
  Five studies were included with a total of 5,165 breast cancer cases and 4,839 healthy controls. Meta-analysis results showed that mutations of rs2075686 (C>T) and rs6869366 (G>T) in the XRCC4 gene were associated with increased risk of breast cancer, while rs2075685 (G>T) and rs10057194 (A>G) might decrease the risk of breast cancer. However, rs1805377 (A>G), rs1056503 (G>T), rs28360317 (ins>del) and rs3734091 (A>G) polymorphisms of XRCC4 gene did not appear to have an influence on breast cancer susceptibility.
  
  
  CONCLUSIONS
  Results from the current meta-analysis suggest that the rs2075685 (G>T) and rs6869366 (G>T) polymorphisms of the XRCC4 gene might increase the risk of breast cancer, whereas rs2075685 (G>T) and rs10057194 (A>G) might be protective factors.
authors.affiliation: Department of Laboratory Medicine, the 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: Ma
authors.forename: Hong
authors.initials: H
authors.lastname: Shang
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D053903:DNA Breaks, Double-Stranded; D059766:DNA End-Joining Repair; D004260:DNA Repair; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D059645:Mutation Rate; D020641:Polymorphism, Single Nucleotide; D012306:Risk
chemical_list: D004268:DNA-Binding Proteins; C101467:XRCC4 protein, human