title: Meta-analysis of the association between hOGG1 Ser326Cys polymorphism and risk of colorectal cancer based on case--control studies.
abstract: OBJECTIVE
  Oxidative DNA damage caused by reactive oxygen species plays an important role in cancer development. The association between colorectal cancer and hOGG1 Ser326Cys polymorphisms has been analyzed in several published studies, but mixed findings have been reported. The main purpose of this study was to integrate previous results and explore whether the polymorphism of hOGG1 is associated with susceptibility to colorectal cancer.
  
  
  METHODS
  PubMed, Embase, Google Scholar, and Cbmdisc were searched for studies on the relationship of hOGG1 SNPs and the incidence of colorectal cancer (CRC). Eligible articles were included for data extraction. The main outcome was the frequency of hOGG1 Ser326Cys polymorphisms between cases and controls. Comparison of the distribution of SNP was mainly performed using Review Manager 5.0.
  
  
  RESULTS
  A total of 4,174 cases and 6,196 controls from 12 studies were included for this meta-analysis. Overall, stratified by ethnicity or population source, no significant associations between the hOGG1 Ser326Cys polymorphism and colorectal cancer risk were found for Cys/Cys allele (OR = 1.146; 95 % CI: 0.978-1.342, P = 0.091), Cys/Cys + Cys/Ser versus Ser/Ser (OR = 1.045; 95 % CI: 0.975-1.121, P = 0.213) Cys/Cys Versus Ser/Ser (OR = 1.243; 95 % CI: 0.979-1.578, P = 0.074) and Cys/Cys versus Cys/Ser + Ser/Ser (OR = 1.198; 95 % CI: 0.959-1.496, P = 0.111) in a recessive model and (OR = 1.494; 95 % CI: 1.023-2.181, P = 0.038) in a homozygote contrast. However, if apart from sensitivity analysis, there was some evidence to indicate that significantly increased risks were found among European plus American subjects, who are mostly Caucasian (OR = 1.444; 95 % CI: 1.017-2.05 Cys/Cys vs. Ser/Cys + Ser/Ser; P = 0.04). In the subgroup analyses, we also did not found any association between hOGG1 Ser326Cys polymorphism and certain populations and smokers.
  
  
  CONCLUSIONS
  This meta-analysis suggests that there is no robust association between hOGG1 Ser326Cys polymorphism and colorectal cancer. Because of the limitation of meta-analysis, this finding demands further investigation.
authors.affiliation: State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, People's Republic of China.
authors.forename: Chang-Long
authors.initials: CL
authors.lastname: Guo
authors.forename: Fei-Fei
authors.initials: FF
authors.lastname: Han
authors.forename: He-Yao
authors.initials: HY
authors.lastname: Wang
authors.forename: Liu
authors.initials: L
authors.lastname: Wang
mesh_terms: D019943:Amino Acid Substitution; D044466:Asian People / Q000235:genetics; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000208:ethnology / Q000235:genetics*; D045647:DNA Glycosylases / Q000235:genetics*; D005060:Europe; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease / Q000208:ethnology / Q000235:genetics*; D005838:Genotype; D006801:Humans; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D012307:Risk Factors; D014481:United States; D044465:White People / Q000235:genetics
chemical_list: D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human