title: Association between the GSTP1 codon 105 polymorphism and gastric cancer risk: an updated meta-analysis.
abstract: OBJECTIVE
  The current meta-analysis was performed to address a more accurate estimation of the association between glutathione S-transferase P1 (GSTP1) codon 105 polymorphism and risk of gastric cancer (GC), which has been widely reported with conflicting results.
  
  
  METHODS
  A comprehensive literature search was conducted to identify all the relevant studies. Fixed or random effect models were selected based on the heterogeneity test. Publication bias was estimated using Begg's funnel plots and Egger's regression test.
  
  
  RESULTS
  A total of 20 studies containing 2,821 GC cases and 6,240 controls were finally included in the analyses. Overall, no significant association between GSTP1 polymorphism and GC risk was observed in worldwide populations. However, subgroup analysis stratified by ethnicity showed that GSTP1 polymorphism was significantly associated with increased risk of GC in Asians (G vs. A, OR = 1.273, 95%CI=1.011-1.605; GG vs. AA, OR=2.103, 95%CI=1.197- 3.387; GG vs. AA+AG, OR =2.103, 95%CI=1.186-3.414). In contrast, no significant association was found in Caucasians in any genetic models, except for with AG vs. AA (OR=0.791, 95%CI=0.669-0.936). Furthermore, the GSTP1 polymorphism was found to be significantly associated with GC in patients with H. pylori infection and in those with a cardiac GC. Subgroup analysis stratified by Lauren's classification and smoking status showed no significant association with any genetic model. No studies were found to significantly influence the pooled effects in each genetic mode, and no potential publication bias was detected.
  
  
  CONCLUSIONS
  This meta-analysis suggested that the GSTP1 polymorphism might be associated with increased risk of GC in Asians, while GSTP1 heterozygote genotype seemed to be associated with reduced risk of GC. Since potential confounders could not be ruled out completely, further studies are needed to confirm these results.
authors.affiliation: Department of Pharmacy, Affiliated Hospital of Inner Mongolia Medical University, Hohhot City, China.
authors.forename: Li-Dao
authors.initials: LD
authors.lastname: Bao
authors.forename: Jian-Xiang
authors.initials: JX
authors.lastname: Niu
authors.forename: Hui
authors.initials: H
authors.lastname: Song
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.forename: Rui-Lian
authors.initials: RL
authors.lastname: Ma
authors.forename: Xian-Hua
authors.initials: XH
authors.lastname: Ren
authors.forename: Xin-Lin
authors.initials: XL
authors.lastname: Wu
mesh_terms: D016022:Case-Control Studies; D003062:Codon / Q000235:genetics*; D020022:Genetic Predisposition to Disease; D051549:Glutathione S-Transferase pi / Q000235:genetics*; D006801:Humans; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012307:Risk Factors; D013274:Stomach Neoplasms / Q000209:etiology*
chemical_list: D003062:Codon; C496556:GSTP1 protein, human; D051549:Glutathione S-Transferase pi