Cyclin D1 Pro241Pro (CCND1-G870A) polymorphism is associated with increased cancer risk in human populations: a meta-analysis.
The G870A polymorphism in the CCND1 gene may influence cancer risk. However, data from published studies with individual low statistical power have been controversial. To evaluate whether combined evidence shows an association between this polymorphism and cancer, we considered all available studies in a meta-analysis. Sixty studies were combined representing data for 18,411 cases and 22,209 controls. In our meta-analysis, we investigated overall sample and two ethnic populations (Caucasians and Asians) as well as nine cancer subtypes. Individuals who are homozygous for A allele (AA) were found to be associated with significantly increased cancer risk in overall sample [odds ratio (OR), 1.23; 95% confidence interval (95% CI), 1.13-1.33; P <or= 0.0001], Caucasians (OR, 1.16; 95% CI, 1.07-1.26; P=0.0002), and Asians (OR, 1.26; 95% CI, 1.14-1.39; P <or= 0.001). Among the nine cancer subtypes investigated, modestly significant risk (ORs, 1.08 to 1.51; P=0.02 to 0.04) was detected in breast, colorectal, head and neck, and other cancers. Highly significant and increased risk was found to be associated with genitourinary (OR, 1.51; 95% CI, 1.20-1.89; P=0.0004) and blood-related cancers (OR, 1.62; 95% CI, 1.28-2.05; P <or= 0.0001). Individuals who are heterozygous for AG were found to be at increased risk in overall, ethnic groups, as well as breast and colorectal cancers. Significant dominant effects seem to prevail in the majority of the categories investigated, where some recessive effects were also detected. Overall, the risk effects associated with this polymorphism were small; however, due its common occurrence, it affects a large portion of the human population (AA, 25%; AG, 50%). Although the independent small risk associated with CCND1-A870G polymorphism is not clinically useful, its interaction with other genetic variants and environmental factors has been shown to be associated with further increase in cancer risk (OR, 1.6-7.1). In conclusion, our study strongly supports the increased cancer risk associated with CCND1-A870G polymorphism in the human population.