title: GSTM1 and GSTT1 polymorphisms are associated with increased bladder cancer risk: Evidence from updated meta-analysis.
abstract: BACKGROUND
  Previous studies have indicated association between GSTM1 and GSTT1 gene polymorphisms and bladder cancer susceptibility, but the results have been inconclusive. Here, we performed a meta-analysis to investigate the association between GSTM1/GSTT1 deletion polymorphisms and bladder cancer susceptibility.
  
  
  METHODS
  We searched for all studies investigating the association between GSTM1 or GSTT1 polymorphism and bladder cancer susceptibility in Pubmed, Web of Knowledge, and the Cochrane Central Search Library. A systematic review and meta-analysis were performed. Subgroup analyses were performed on different ethnicity, population-based and smoking status.
  
  
  RESULTS
  Our search identified 63 studies. GSTM1 null, GSTT1 null and GSTM1/GSTT1 double-null genotypes were associated with increased risk of bladder cancer (OR: 1.36 95% CI: 1.25-1.47, P<0.01; OR: 1.13 95% CI: 1.02-1.25, P<0.01; OR: 1.84 95% CI: 1.50-2.26, P<0.01). Subgroup analyses indicated that the GSTM1-null genotype was associated with increased risk of bladder cancer in Caucasians and Asians, while the GSTT1-null genotype was associated with increased risk of bladder cancer in Caucasians. The GSTM1/GSTT1 double-null genotype was associated with increased risk of bladder cancer in Caucasians, Asians, and Africans. Stratified analyses of population-based associations indicated increased bladder cancer risk associated with GSTM1-null and GSTM1/GSTT1 double-null genotypes in hospital-based and population-based studies. GSTM1 deletion was associated with increased bladder cancer risk in both smokers and nonsmokers. Non-smokers with the GSTM1/GSTT1 double-null genotype had an increased bladder cancer risk.
  
  
  CONCLUSIONS
  This meta-analysis demonstrates that the GSTM1-null, GSTT1-null, and GSTM1/GSTT1 double-null genotypes are associated with increased bladder cancer risk.
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Cui
authors.initials: C
authors.lastname: Yu
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Hequn
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Longfei
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Wang
authors.initials: W
authors.lastname: Long
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhi
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Zeng
authors.initials: Z
authors.lastname: Feng
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Jinbo
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Li
authors.initials: L
authors.lastname: Chao
authors.affiliation: Department of Urology, Xiangya Hospital, Central South University, Changsha, Hunan 410000, China.
authors.forename: Zu
authors.initials: Z
authors.lastname: Xiongbing
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D020022:Genetic Predisposition to Disease; D005838:Genotype; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D016017:Odds Ratio; D011110:Polymorphism, Genetic; D017594:Publication Bias; D012306:Risk; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology / Q000235:genetics*
chemical_list: D005982:Glutathione Transferase; C413545:glutathione S-transferase T1
keywords: GSTM1; GSTT1; bladder cancer; polymorphism