Association between the G870A polymorphism of Cyclin D1 gene and glioma risk

Previous studies have shown the association of the Cyclin D1 (CCND1) G870A polymorphism with glioma risk, but the findings are inconsistent and inconclusive. To shed some light on the findings across individual studies and acquire a quantitative assessment of this association, we conducted a meta-analysis of all published case–control studies thus far. Four independent studies with a total of 690 cases and 1,014 controls were identified after a systematic search of the PubMed, Embase, Web of Science, and Wanfang databases. The strength of the association between the CCND1 G870A polymorphism and glioma risk was estimated by the pooled odds ratios (ORs) with 95 % confidence intervals (95 %CIs). Subgroup analysis by ethnicity was also performed. Overall, a statistically significant association was found between the CCND1 G870A polymorphism and glioma risk in three genetic models (OR_{A vs. G} = 1.178, 95 %CI 1.025–1.354, P _OR = 0.021; OR_{AA vs. GG} = 1.328, 95 %CI 1.007–1.750, P _OR = 0.045; OR_{AA + AG vs. GG} = 1.253, 95 %CI 1.006–1.516, P _OR = 0.044). In subgroup analysis, the pooled ORs suggested that the CCND1 G870A polymorphism was associated with an increased risk of glioma in Caucasians under the heterozygote and dominant genetic models (OR_{AG vs. GG} = 1.329, 95 %CI 1.001–1.766, P _OR = 0.049; OR_{AA + AG vs. GG} = 1.332, 95 %CI 1.019–1.740, P _OR = 0.036). The meta-analysis suggests that the CCND1 G870A polymorphism is a risk factor for the development of glioma.