title: An association between hOGG1 Ser326Cys polymorphism and the risk of bladder cancer in non-smokers: a meta-analysis.
abstract: BACKGROUND
  Bladder cancer results from complex interactions between many genetic and environment factors. The polymorphism Ser326Cys in hOGG1 gene has been reported to be associated with bladder cancer in some studies, though the results remain inconclusive. To explore this relationship of hOGG1 polymorphism and the susceptibility for bladder cancer and the impact of smoking exposures, a cumulative meta-analysis was performed in this study.
  
  
  METHODS
  We extracted the data from the Pubmed database up to January 9, 2012 using the search phrases "hOGG1, Ser326Cys polymorphism and bladder cancer". Seven case-control studies were identified, including 2474 patients and 2408 controls. Four of them provided the analysis of smoking effects, with 1372 smokers and 947 non-smokers. The odds ratios (ORs) and associated 95 % confidence intervals (CIs) were calculated using fixed- or random- effects models.
  
  
  RESULTS
  Regarding the overall association between the hOGG1 326Cys allele and bladder cancer risk, the meta-analysis did not reveal a significant effect in the additive model (OR: 1.06, 95 % CI: 0.96-1.26; p = 0.49), the recessive genetic model (OR: 1.05, 95 % CI: 0.65-1.70; p = 0.85) or the dominant genetic model (OR: 1.07, 95 % CI: 0.87-1.32; p = 0.53). Similarly, no significant relationship was observed in the stratified analysis by ethnicity, study design and Hardy-Weinberg equilibrium (all p > 0.05). In the non-smokers, however, hOGG1 326Cys allele significantly increased the risk for bladder cancer and the ORs in the additive model, homozygote contrast and recessive genetic model were 1.59 (p = 0.02), 2.53(p = 0.003) and 2.41(p = 0.0005), respectively. Nevertheless, in the smoker subgroup, similar findings could not be found in all genetic models (all p > 0.05).
  
  
  CONCLUSIONS
  The association between the hOGG1 326Cys allele and bladder cancer was significant in non-smoker population, while was non-detectable in common or smoker populations. This meta-analysis suggests that the hOGG1 Ser326Cys polymorphism may be a risk factor for bladder cancer without exposure to smoking. Further functional studies are needed to elucidate the gene polymorphism-bladder cancer relationship and gene-environment interactions.
authors.affiliation: Department of Urology, the Affiliated Drum Tower Hospital of Nanjingm, University Medical School, Nanjing 210008, China.
authors.forename: Changwei
authors.initials: C
authors.lastname: Ji
authors.forename: Zhao
authors.initials: Z
authors.lastname: Liu
authors.forename: Huimei
authors.initials: H
authors.lastname: Chen
authors.forename: Hongqian
authors.initials: H
authors.lastname: Guo
authors.forename: Changjian
authors.initials: C
authors.lastname: Liu
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D045647:DNA Glycosylases / Q000235:genetics*; D005787:Gene Frequency; D059647:Gene-Environment Interaction; D020022:Genetic Predisposition to Disease; D005838:Genotype; D006801:Humans; D020641:Polymorphism, Single Nucleotide; D017594:Publication Bias; D012307:Risk Factors; D012907:Smoking; D001749:Urinary Bladder Neoplasms / Q000235:genetics*
chemical_list: D045647:DNA Glycosylases; C479058:oxoguanine glycosylase 1, human