Association between IL-17A G197A polymorphism and gastric cancer risk: an updated meta-analysis based on 6,624 cases and 7,631 controls

Purpose Previous studies investigating the association between interleukin-17A (IL-17A) G197A polymorphism and gastric cancer risk have provided inconsistent results. We, therefore, conducted this meta-analysis to clarify the association between IL-17A G197A polymorphism and gastric cancer risk. Methods We searched PubMed, Excerpta Medica Database, and CNKI databases to identify relevant studies up to June 10, 2017. A total of 16 case-control studies including 6,624 cases and 7,631 controls were identified. Results Overall, significant associations between IL-17A G197A polymorphism and gastric cancer risk were observed (A vs G: OR =1.24, 95% CI =1.14-1.36; AA vs GG: OR =1.63, 95% CI =1.35-1.96; GA vs GG: OR =1.12, 95% CI =1.01-1.25; AA+GA vs GG: OR =1.23, 95% CI =1.11-1.35; AA vs GA+GG: OR =1.54, 95% CI =1.27-1.87). Similar associations were also observed in Asian population (A vs G: OR =1.25, 95% CI =1.15-1.37; AA vs GG: OR =1.62, 95% CI =1.33-1.97; GA vs GG: OR =1.16, 95% CI =1.07-1.25; AA+GA vs GG: OR =1.24, 95% CI =1.15-1.33; AA vs GA+GG: OR =1.51, 95% CI =1.23-1.85), in Caucasian population (AA vs GA+GG: OR =2.19, 95% CI =1.40-3.44), and in the hospital-based controls' subgroup (A vs G: OR =1.30, 95% CI =1.17-1.45; AA vs GG: OR =1.81, 95% CI =1.46-2.25; AA+GA vs GG: OR =1.27, 95% CI =1.12-1.43; AA vs GA+GG: OR =1.71, 95% CI =1.34-2.18). Conclusions The current meta-analysis suggests that IL-17A G197A polymorphism might enhance gastric cancer risk.