title: Association of GSTP1 Ile105Val polymorphism and risk of head and neck cancers: a meta-analysis of 28 case-control studies.
abstract: OBJECTIVE
  The Glutathione S-transferase P1 (GSTP1) polymorphism have been considered a risk modifier for developing head and neck cancer (HNC) in many studies; however, the results of such studies are inconsistent. The aim of this study was to evaluate the possible association between the GSTP1 Ile105Val polymorphism and risk of HNC.
  
  
  METHODS
  We performed a search in the relevant electronic database and a meta-analysis based on 28 published case-control studies that included 6,404 cases and 6,523 controls. To take into account the possibility of heterogeneity across the studies, a Chi-square based I(2)-statistic test was performed. Crude pooled odds ratios (ORs) with 95% confidence intervals (CIs) were assessed using both fixed-effects and random-effects models.
  
  
  RESULTS
  The results of this meta-analysis showed that the GSTP1 Ile105Val polymorphism was not significantly associated with risk of HNC in the overall study population (pooled OR 1.00, 95% CI 0.92-1.09) or in subgroup analyses stratified by ethnicity, sample size, tumor site or publication year. Moreover, substantial evidence of heterogeneity among the studies was observed. Publication year was identified as the main cause of heterogeneity.
  
  
  CONCLUSIONS
  This meta-analysis does not support a significant association between the GSTP1 Ile105Val polymorphism and risk of HNC.
authors.affiliation: Department of Otorhinolaryngology-Head & Neck Surgery, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China.
authors.forename: Juntian
authors.initials: J
authors.lastname: Lang
authors.forename: Xicheng
authors.initials: X
authors.lastname: Song
authors.forename: Jinwei
authors.initials: J
authors.lastname: Cheng
authors.forename: Shuwei
authors.initials: S
authors.lastname: Zhao
authors.forename: Jingping
authors.initials: J
authors.lastname: Fan
mesh_terms: D016022:Case-Control Studies; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D051549:Glutathione S-Transferase pi / Q000235:genetics*; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D020125:Mutation, Missense; D011110:Polymorphism, Genetic; D017594:Publication Bias; D012044:Regression Analysis
chemical_list: C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi