CCND1 G870A polymorphism is associated with increased risk of colorectal cancer, especially for sporadic colorectal cancer and in Caucasians: a meta-analysis

Aims: To detect the association between G870A polymorphism of cyclin D1 (CCND1) gene and colorectal cancer.

Methods: We performed a systematic literature and abstract search using PubMed, EMBase digital database. Keywords included CCND1, cyclin D1, polymorphism, SNP, colon cancer, rectal cancer and colorectal cancer. "And", "OR" and "NOT" were used as conjunction to narrow and widen the search. Data were extracted by two investigators independently, and meta-analysis was carried out by using Review Manager 4.2.8. The following pairwised combinations of genotypes for the CCND1 G870A polymorphism were evaluated: AA vs. GG, AG vs. GG, AA+AG vs. GG. Subsequently, sub-group analyses for cancer type, ethnicity, and the family history were performed. Sensitivity analysis was conducted by excluding the articles deviated from Hardy-Weinberg equilibrium.

Results: Using GG genotype as a reference, A carriers were associated with a significantly increased cancer risk (OR=1.15, 95%CI=1.06-1.25, P=0.001, P(heterogeneity)=0.130), especially with rectal cancer (OR=1.24, 95%CI=1.02-1.51, P=0.030, P(heterogeneity)=0.570) and sporadic colorectal cancer (OR=1.26, 95%CI=1.08-1.46, P=0.003, P(heterogeneity)=0.730). The effect of A carriers on cancer also existed in Caucasians (OR=1.19, 95%CI=1.06-1.32, P=0.002, P(heterogeneity)=0.100).

Conclusions: CCND1 G870A polymorphism is associated with the increased risk of colorectal cancer, especially for sporadic colorectal cancer and in Caucasians.