Association between cytotoxic T-lymphocyte antigen-4 +49A/G polymorphism and colorectal cancer risk: a meta-analysis

The Cytotoxic T-Lymphocyte Antigen-4 (CTLA-4) gene has been implicated in the development of colorectal cancer (CRC). However, the results are inconsistent. In this study, we performed a meta-analysis to assess the associations between the CTLA-4 +49A/G polymorphism and risk of CRC. Relevant studies were identified using PubMed, Web of Science, CNKI and WanFang databases up to November 10, 2014. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the association using the fixed or random effect model. A total of 8 case-control studies, including 1180 cases and 2110 controls, were included. Overall, a significant association between the CTLA-4 +49A/G polymorphism and CRC risk was found (dominant model: OR=1.63, 95% CI: 1.09-2.43; AG vs. AA: OR=1.69, 95% CI: 1.15-2.48). In the subgroup analysis by ethnicity, we observed a significant association in Asian descent (dominant model: OR=2.42, 95% CI: 1.40-4.16; AG vs. AA: OR=2.39, 95% CI: 1.52-3.76), but not among Europeans; when stratified by source of control, no significant association was detected in both population-based and hospital-based populations. This meta-analysis demonstrated that the CTLA-4 +49A/G polymorphism significantly increases the risk of CRC, especially for Asians.