The 765G>C Polymorphism in the Cyclooxygenase-2 Gene and Gastric Cancer Risk: an Update by Meta-analysis

Background: The 765G>C polymorphism in cyclooxygenase-2 (COX-2) gene has been extensively investigated for association with gastric cancer (GC). However, the results of different studies have been inconsistent. The aim of this study is to comprehensively evaluate the genetic risk of -765G>C polymorphism in the COX-2 gene for GC. Materials and Methods: We searched Pubmed, Embase, Medline, CNKI database, Wanfang database, Weipu database, and Chinese Biomedical database, covering all publications (last search been performed on Jan 10, 2014). Statistical analyses were performed using Revman 5.2 and STATA 10.0 software. Results: A total of 1,874 cases and 3,005 controls in 10 case-control studies were included in this meta-analysis. The results indicated that the variant C allele carriers (GC+CC) had a 69% increased risk of GC when compared with the homozygote GG (odds ratio (OR)=1.69, 95% confidence interval (CI), 1.10-2.61 for GC+CC vs GG). In the subgroup analysis by ethnicity, significant elevated risks were associated with C allele carriers in Asians (OR=1.75, 95% CI=1.40-2.18, and p<0.00001) and in Indians (OR=8.38, 95% CI=4.34-16.16, and p<0.00001) but not in Caucasians (OR=1.07, 95% CI=0.81-1.42, and p=0.62) or in Dutch (OR=0.53, 95% CI=0.33-0.87, and p=0.01). In the subgroup analysis by Helicobacter pylori (H. pylori) status, a significantly increased risk was identified among H. pylori (+) (OR=3.58, 95% CI=2.33-3.50, and p<0.00001) and H. pylori (-) (OR=2.32, 95% CI=1.46-3.69, and p=0.0004). Conclusions: This meta-analysis suggested that the -765G>C polymorphism in the COX-2 gene could be a risk factor for GC in Asians and Indians.