Association Studies of CYP1A1 Exon7 Polymorphism and -GSTM1 Interaction with Esophageal Cancer Risk: a Meta-Analysis in the Chinese Population.

Background: Although many epidemiological studies have investigated the CYP1A1 exon7 polymorphism and -GSTM1 interaction with esophageal cancer (EC), definite conclusions cannot be drawn. This study was conducted to explore this association in the Chinese population using meta-analysis.

Methods: Relevant studies were identified from PubMed, Springer Link, Ovid, Chinese Wanfang Data Knowledge Service Platform, Chinese National Knowledge Infrastructure, and Chinese Biology Medicine databases published through August 2015. The association of CYP1A1 exon7 polymorphisms and EC risk was estimated by odds ratio (ORs) with 95% confidence intervals (CIs). In addition, the interaction between the CYP1A1 exon7 and GSTM1 genotypes was assessed.

Results: A total of 13 case-control studies including 1781 EC cases and 1996 controls were included in this metaanalysis. Overall, significantly increased EC risk was associated with the CYP1A1 exon7 polymorphism (G vs. A OR = 1.36, 95% CI = 1.14 - 1.64; GG vs. AA: OR = 1.85, 95% CI = 1.22 - 2.79; GG vs. AG: OR = 1.41, 95% CI = 1.01 - 1.96; GG + AG vs. AA: OR = 1.47, 95% CI = 1.28 - 1.68; GG vs. AA + AG: OR = 1.60, 95% CI = 1.10 - 2.31). In a subgroup analyses stratified by geographic areas, histopathology type and source of controls, the significant risk was found in hospital-based population, in South and North China. Analysis of CYP1A1- GSTM1 interaction did find synergistic interaction between these two genes.

Conclusions: This meta-analysis provides the evidence that CYP1A1 exon7 polymorphism may contribute to the EC development in the Chinese population, and CYP1A1- GSTM1 interaction might elevate the risk.