Cyclooxygenase-2 polymorphisms were associated with the risk of gastric cancer: evidence from a meta-analysis based on case-control studies

The associations between cyclooxygenase-2 (COX-2) polymorphisms (-765G > C, -1195G > A, and -587G > A) and risk of gastric cancer have been investigated, but the results were inconsistent. The aim of this study was to explore the associations between COX-2 polymorphisms and risk of gastric cancer using a meta-analytic method. We searched the databases of PubMed, Embase, and Wanfang (Chinese database) to identify the eligible studies. Odds ratio and 95 % confidence interval (OR and 95 % CI) were used as effect size, and combined analyses were conducted using fixed- or random-effects model. Overall, ten studies for COX-2-765G > C, six studies for -1195G > A, and three studies for -587G > A were included in this study. The results for combined analysis for COX-2-765G > C indicated that C allele was significantly associated with increased risk of gastric cancer compared with G allele, especially for Asians (OR and 95 % CI: 1.58 (1.06-2.35), P (z-test) = 0.03, and P (heterogeneity) < 0.01 for CC+GC vs. GG). In addition, the A allele of COX-2-1195G > A was also significantly associated with risk of gastric cancer compared with G allele (OR and 95 % CI: 1.20 (1.09-1.32), Pz-test < 0.001, and P-heterogeneity = 0.82 for A carriers vs. G carriers). In contrast, the COX-2-587G > A polymorphism was not associated with risks of gastric cancer. In summary, this meta-analysis indicated that the COX-2-765G > C and -1195G > A polymorphisms were significantly associated with risk of gastric cancer development.