title: Null genotype of glutathione S-transferase Tl contributes to colorectal cancer risk in the Asian population: a meta-analysis.
abstract: OBJECTIVE
  Previous studies investigating the association between the glutathione S-transferase Tl (GSTT1) null genotype and colorectal cancer (CRC) risk in the Asian population have reported controversial results. Thus, a meta-analysis was performed to clarify the effect of the GSTT1 null genotype on CRC risk in the Asian population.
  
  
  METHODS
  A comprehensive study was conducted, and 12 case-control studies were finally included, involving a total of 4517 CRC cases and 6607 controls. Subgroup analyses were performed by the sample size.
  
  
  RESULTS
  A meta-analysis of all 12 studies showed that the GSTT1 null genotype was significantly associated with an increased CRC risk in the Asian population (odds ratio [OR] = 1.10, 95% confidence interval [CI] = 1.02-1.19, the P-value of the OR [P(OR)] = 0.02, the value of the heterogeneity analysis [I(2)] = 42%). A more obvious association was observed after the heterogeneity was eliminated by excluding one study (OR = 1.15, 95% CI: 1.06-1.25, P(OR) = 0.001, I(2) = 0%). This association was further identified by both subgroup analyses and a sensitivity analysis.
  
  
  CONCLUSIONS
  This meta-analysis suggests that the GSTT1 null genotype contributes to an increased colorectal cancer risk in the Asian population.
authors.affiliation: State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Medicine, Tsinghua University, Beijing, China.
authors.forename: Shan
authors.initials: S
authors.lastname: Zhong
authors.forename: Jia-He
authors.initials: JH
authors.lastname: Yang
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Bing-Hua
authors.initials: BH
authors.lastname: Jiao
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Chang
mesh_terms: D001208:Asia / Q000453:epidemiology; D044466:Asian People / Q000235:genetics*; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D015179:Colorectal Neoplasms / Q000201:enzymology / Q000208:ethnology / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010641:Phenotype; D018570:Risk Assessment; D012307:Risk Factors
chemical_list: C413545:glutathione S-transferase T1; D005982:Glutathione Transferase