title: Association between polymorphisms in XRCC1 gene and clinical outcomes of patients with lung cancer: a meta-analysis.
abstract: BACKGROUND
  X-ray repair cross-complementing group 1 (XRCC1) protein plays an important role in the repair of DNA damage and adducts. Single nucleotide polymorphisms (SNPs) of XRCC1 are suspected to have some relationship with response to chemotherapy and overall survival of lung cancer. This meta-analysis aimed to summarize published data on the association between the commonest SNPs of XRCC1 (Arg194Trp, C > T, rs1799782 and Arg399Gln, G > A, rs25487) and clinical outcome of lung cancer patients.
  
  
  METHODS
  We retrieved the relevant articles from PubMed, EMBASE and the China National Knowledge Infrastructure (CNKI) databases. Studies were selected using specific inclusion and exclusion criteria. Primary outcomes included objective response (i.e., complete response + partial response vs. progressive disease + stable disease) and overall survival (OS). Odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI) were estimated. All analyses were performed using the Stata software.
  
  
  RESULTS
  Twenty-two articles were included in the present analysis. XRCC1 Arg194Trp and Arg399Gln polymorphisms were significantly associated with response to treatment in lung cancer patients. Patients with C/T genotype, T/T genotype and minor variant T allele at Arg194Trp were more likely to respond to platinum-based chemotherapy compared with those with C/C genotype (C/T vs. C/C: OR, 2.54; 95%CI, 1.95-3.31; T/T vs. C/C: OR, 2.06; 95%CI, 1.39-3.06; C/T+T/T vs. C/C: OR, 2.42; 95% CI, 1.88-3.10). For XRCC1 Arg399Gln, G/A genotype, A/A genotype and minor variant A allele were associated with objective response in all patients (G/A vs. G/G: OR, 0.67; 95%CI, 0.50-0.90; A/A vs. G/G: OR, 0.43; 95%CI, 0.25-0.73; A/A+G/A vs. G/G: OR, 0.63; 95%CI, 0.49-0.83). Both G/A and A/A genotypes of XRCC1 Arg399Gln could influence overall survival of lung cancer patients (G/A vs. G/G: HR, 1.23; 95%CI, 1.06-1.44; A/A vs. G/G: HR, 2.03; 95%CI, 1.20-3.45). Interaction analysis suggested that compared with the patients carrying C/T+T/T genotype at XRCC1 194 and G/G genotype at XRCC1 399, the patients carrying 194 C/C and 399 G/A+A/A or 194 C/C and 399 G/G genotype showed much worse objective response.
  
  
  CONCLUSIONS
  Genetic polymorphisms in XRCC1 gene might be associated with overall survival and response to platinum-based chemotherapy in lung cancer patients.
authors.affiliation: China Medical University, Shenyang 110001, PR China.
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Cui
authors.forename: Zhihua
authors.initials: Z
authors.lastname: Yin
authors.forename: Xuelian
authors.initials: X
authors.lastname: Li
authors.forename: Wei
authors.initials: W
authors.lastname: Wu
authors.forename: Peng
authors.initials: P
authors.lastname: Guan
authors.forename: Baosen
authors.initials: B
authors.lastname: Zhou
mesh_terms: D000970:Antineoplastic Agents / Q000627:therapeutic use; D004260:DNA Repair / Q000235:genetics; D004268:DNA-Binding Proteins / Q000235:genetics*; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000235:genetics* / Q000401:mortality; D017671:Platinum Compounds / Q000627:therapeutic use; D020641:Polymorphism, Single Nucleotide; D016019:Survival Analysis; D000076105:X-ray Repair Cross Complementing Protein 1
chemical_list: D000970:Antineoplastic Agents; D004268:DNA-Binding Proteins; D017671:Platinum Compounds; D000076105:X-ray Repair Cross Complementing Protein 1; C000619371:XRCC1 protein, human