GSTM1 and GSTT1 Gene Polymorphisms, Gene-Gene Interaction, and Esophageal Carcinoma Risk: Evidence from an Updated Meta-Analysis

Background: Published data regarding the association between GSTM1 and/or GSTT1 gene polymorphisms and esophageal cancer (EC) susceptibility remain inconclusive. To clarify these associations, a meta-analysis was conducted. Methods: We conducted a comprehensive search in PubMed, Embase, and the China National Knowledge Infrastructure (CNKI) for all such manuscripts published as of May 1, 2017. The pooled odds ratio (ORs) with confidence intervals (95% CI) were estimated for each study to assess the strength of the association. A subgroup analysis, a sensitivity analysis, and a publication bias analysis were also performed. Results: Data from 41 studies comprising 5291 EC cases and 8191 controls were available for analysis of the GSTM1 polymorphism, and data from 31 studies comprising 4330 EC cases and 6558 controls were available for analysis of the GSTT1 polymorphism. Analyses of the GSTM1 polymorphisms demonstrated that there was a significantly increased EC risk in GSTM1 null genotype carriers (OR = 1....