Cyclin D1 G870A polymorphism and colorectal cancer susceptibility: a meta-analysis of 20 populations

Purpose Studies investigating the association between genetic polymorphism of cyclin D1 (CCND1) G870A and risk of colorectal cancer (CRC) reported conflicting results. In order to derive a more precise estimation of the relationship, a meta-analysis was performed. Materials and methods We performed an extensive search of relevant studies and carried out a meta-analysis, including 20 studies with 5,975 cases and 8,333 controls, to obtain a more precise estimate. Results Overall, significantly elevated colorectal cancer risk was associated with variant allele 870A when all studies were pooled (AA vs. GG: OR = 1.23, 95% CI = 1.04–1.44; GA vs. GG: OR = 1.13, 95% CI = 1.01–1.26; dominant model: OR = 1.16, 95% CI = 1.03–1.31). In the subgroup analysis by ethnicity, significantly increased risks were detected among Caucasians (AA vs. GG: OR = 1.27, 95% CI = 1.04–1.44; dominant model: OR = 1.17, 95% CI = 1.02–1.34).We also observed sporadic CRC with an increased cancer susceptibility (AA vs. GG: OR = 1.24, 95% CI = 1.04–1.48; dominant model: OR = 1.17, 95% CI = 1.04–1.33), when colorectal cancer was stratified into sporadic CRC and hereditary nonpolyposis colorectal cancer (HNPCC). However, no significant associations were found in both Asians and HNPCC patients for all genetic models. Conclusion Result suggests that the cyclin D1 870A allele is a low-penetrant risk factor for developing sporadic colorectal cancer, especially among Caucasians.