Association of IL-17A and IL-17F polymorphisms with gastric cancer risk in Asians: a meta-analysis.

Increasing number of studies focused on the association of IL-17A rs2275913 and IL-17F rs763780 polymorphisms with gastric cancer (GC) risk. However, the results were inconsistent. To elucidate the exact association, we performed the present meta-analysis. Databases including PubMed, Web of knowledge and Chinese National Knowledge Infrastructure (CNKI) were systematically searched for potentially eligible literatures. Odds ratios (OR) and their 95% confidence interval (CI) were used to evaluate the strength of association. Eight studies for IL-17A rs2275913 (3345 cases and 4427 controls) and five studies for IL-17F rs763780 (1784 cases and 2592 controls) were finally included. The results indicated that individuals with AA genotype of IL-17A rs2275913 polymorphism were associated with increased GC risk compared with wild-type GG (OR=1.61, 95% CI=1.17-2.23, P=0.004); A allele was significantly associated with increased GC risk compared with G allele (OR=1.22, 95% CI=1.06-1.41, P=0.007). IL-17F rs763780 polymorphism was also significantly associated with increased GC risk (CC vs. CT: OR=1.40, 95% CI=1.04-1.88, P=0.025; CT vs. TT: OR=1.35, 95% CI=1.16-1.58, P<0.001; C allele vs. T allele: OR=1.30, 95% CI=1.15-1.47, P<0.001). In summary, IL-17A rs2275913 A/G polymorphism and IL-17F rs763780 C/T polymorphism might be associated with increased GC risk in Asians. Further large-scale studies are still required to confirm the results of this meta-analysis.