Cyclin D1 G870A polymorphism and breast cancer risk: A meta-analysis involving 23,998 subjects

Cyclin D1 (CCND1) plays an essential role in tumor development and progression through regulating the cell transition from G1 to the proliferative S phase. The CCND1 G870A polymorphism has been associated with an increased susceptibility to squamous cell carcinoma of the head and neck, bladder, prostate, and gastric cardiac cancers. There are a number of studies that explored the relationship between CCND1 G870A polymorphism and breast cancer risk, with inconsistent conclusions. In order to better define the predictive value of CCND1 G870A polymorphism in breast cancer, we searched PubMed and EBSCO for relevant publications. A total of 13 studies were indentified, which included 11,235 cases and 12,763 controls. We calculated the summary odds ratios and the corresponding 95% confidence interval. Our meta-analysis showed that carriers of AA genotype have a significantly higher risk in developing breast cancer compared with that of GG genotype (OR = 1.08, 95% CI = 1.01-1.17, p> = 0.03) in overall population. Furthermore, in subgroup analysis, CCND1 G870A polymorphism was associated with a marginally increased risk of breast cancer for Chinese compared to Caucasian populations with an OR = 1.14, 95% CI = 1.00-1.20, ptrend = 0.06 for AA + GA versus GG, if the controls were hospital-based population with an OR = 1.21, 95% CI = 0.99-1.47, p = 0.06 for AA versus GG and if the distributions of genotypes in control groups were consistent with the Hardy-Weinberg equilibrium (HWE) with an OR = 1.08, 95% CI = 1.00-1.15, p = 0.04 for AA versus GA + GG. Our meta-analysis represents the largest study to date indicating that the G870A polymorphism in CCND1 confers an increased risk for breast cancer. Further studies are warranted to explore the preventive measures to detect and manage the breast cancers attributable to the G870A polymorphism.