The Cox-2 21195 G> A polymorphism and cancer risk: a meta-analysis of 25 case–control studies

Cyclooxygenase 2 (Cox-2, a rate-limiting enzyme in the conversion of arachidonic acid to prostanoids) has been implicated in several physiological and pathological pro-cesses, and it has been reported that polymorphisms in the regulatory region of Cox-2 might influence its expression, contributing to the interindividual susceptibility to cancer. However, results from published studies on the association between the Cox-2 21195G> A polymorphism and the risk of cancer are conflicting. We performed a meta-analysis based on 25 case–control studies, including a total of 9482 cancer cases and 12 206 controls to derive a more precise estimation of the association and its possible influence on cancer risk. We used odds ratios (ORs) with 95 % confidence intervals (CIs) to assess the strength of the association. The overall results indicated that the variant genotypes moderately increased risk of cancer (AA/AG versus GG, OR 5 1.15, 95 % CI: 1.02–1.31). In the stratified analysis for the 21195G> A polymorphism, a proximate association was observed in Asian populations (AA/AG versus GG, OR 5 1.28, 95 % CI: 1.12–1.46), but no significant association except for oesophageal cancer and ‘others ’ was found when stratified by cancer type. In conclusion, our meta-analysis indicates that 21195G> A of Cox-2 is a low penetration risk factor for cancer