title: Meta-analysis of GSTM1 and GSTT1 polymorphisms and risk of nasopharyngeal cancer.
abstract: BACKGROUND
  Studies of associations between genetic polymorphism of glutathione S-transferase M1 (GSTM1) and glutathione S-transferase T1 (GSTT1) with risk of nasopharyngeal cancer (NPC) have generated conflicting results. Thus, a meta-analysis was performed to clarify the effects of GSTM1 and GSTT1 polymorphisms on the risk of developing NPC.
  
  
  METHODS
  A literature search in two electronic databases namely PubMed and EMBASE up to December 2012 was conducted and eligible papers were finally selected based on the inclusion and exclusion criteria. The pooled odds ratio (OR) and presence of heterogeneity and publication bias in those studies were evaluated.
  
  
  RESULTS
  A total of 9 studies concerning nasopharyngeal cancer were evaluated. Analyses of all relevant studies showed increased NPC risk to be significantly associated with the null genotypes of GSTMI (OR=1.43, 95%CI 1.24-1.66) and GSTT1 (OR=1.28, 95%CI=1.09-1.51). In addition, evidence of publication bias was detected among the studies on GSTM1 polymorphism.
  
  
  CONCLUSIONS
  This meta-analysis demonstrated the GSTM1 and GSTT1 null genotypes are associated with an increased risk of NPC.
authors.affiliation: Department of Public Health Dentistry, MR Ambedkar Dental College, Bangalore, India. archanakm20@gmail.com
authors.forename: Archana Krishna
authors.initials: AK
authors.lastname: Murthy
authors.forename: Vinod
authors.initials: V
authors.lastname: Kumar
authors.forename: K P
authors.initials: KP
authors.lastname: Suresh
mesh_terms: D016022:Case-Control Studies; D020022:Genetic Predisposition to Disease; D005982:Glutathione Transferase / Q000235:genetics*; D006801:Humans; D009303:Nasopharyngeal Neoplasms / Q000209:etiology*; D011110:Polymorphism, Genetic / Q000235:genetics*; D011379:Prognosis; D012307:Risk Factors
chemical_list: D005982:Glutathione Transferase; C413545:glutathione S-transferase T1