Association between the Interleukin-17A -197G>A (rs2275913) Polymorphism and Risk of Digestive Cancer

Interleukin-17A (IL-17A) is a multifunctional cytokine which plays a crucial role in the initiation andprogression of cancer. To date, several studies have investigated associations between IL-17A -197G>A (rs2275913)polymorphism and digestive cancer risk, but the results remain conflicting. We here aimed to confirm the roleof this single nucleotide polymorphism (SNP) in susceptibility to digestive cancer through a systemic reviewand meta-analysis. Ten eligible case-control studies were identified by searching electronic databases, involving3,087 cases and 3,815 controls. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were usedto estimate the strength of the association. The results of overall analyses indicated that the variant A allele wasassociated with an increased risk of digestive cancer (AA vs GG: OR=1.51, 95%CI=1.18-1.93; AA vs GG+GA:OR=1.45, 95%CI=1.12-1.87; A vs G: OR=1.21, 95%CI=1.05-1.39). In subgroup analysis stratified by specificcancer type, elevated risk among studies of gastric cancer was found (AA vs GG: OR=1.68, 95%CI=1.24-2.28;AA vs GG+GA: OR=1.62, 95%CI=1.16-2.26; A vs G: OR=1.23, 95%CI=1.04-1.46). According to ethnicity, therewas evidence in the Asian populations for an association between this polymorphism and cancer risk (GA vs GG:OR=1.19, 95%CI=1.05-1.36; AA vs GG: OR=1.56, 95%CI=1.15-2.12; AA+GA vs GG: OR=1.28, 95%CI=1.13-1.44; AA vs GG+GA: OR=1.42, 95%CI=1.01-2.00; A vs G: OR=1.24, 95%CI=1.08-1.44), while in the Caucasianpopulations an association was found in the recessive model (AA vs GG+GA: OR=1.62, 95%CI=1.17-2.24). Inconclusion, the results of this meta-analysis suggest that the IL-17A -197G>A polymorphism contributes to anincreased risk of human digestive cancer, both in the Asian and Caucasian populations and especially for gastriccancer.