The Cyclin D1 G870A Polymorphism and Colorectal Cancer Susceptibility: A Meta-analysis of 20 Populations

Purpose: Studies of the association between the cyclin D1 (CCND1) G870A genetic polymorphism and risk of colorectal cancer (CRC) have generated conflicting results. In order to derive a more precise estimation, a meta-analysis was here performed. Materials and methods: An extensive search of relevant studies was carried out as a meta-analysis of twenty studies with 5,975 cases and 8,333 controls. Results: Overall, a 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; and dominant model: OR = 1.17, 95%CI = 1.02-1.34). With stratification into sporadic CRC and hereditary nonpolyposis colorectal cancer (HNPCC), the former demonstrated 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). However, no significant associations were found in either Asians or HNPCC patients for any genetic model. Conclusion: The results suggest that the cyclin D1 870A allele is a low-penetrant risk factor for development of sporadic colorectal cancer, especially among Caucasians.