Effects of the cyclin D1 polymorphism on lung cancer risk--a meta-analysis.

BACKGROUND Cyclin D1 (CCND1) is critical in the transition of the cell cycle from G1 to S phases and unbalanced cell cycle regulation is a hallmark of carcinogenesis. A number of studies conducted to assess the association between CCND1 G870A polymorphism and susceptibility to lung cancer have yielded inconsistent and inconclusive results. In the present study, the possible association above was assessed by a meta-analysis. METHODS Eligible articles were identified for the period up to November 2011. Pooled odds ratios (OR) with 95% confidence intervals (95%CI) were appropriately derived from fixed effects or random-effects models. Sensitivity analysis excluding studies whose genotype frequencies in controls significantly deviated from the Hardy-Weinberg equilibrium (HWE) was performed. RESULTS Ten case-control studies with a total of 10,548 subjects were eligible. At the overall analysis the CCND1 870A allele appeared to be associated with elevated lung cancer risk (for allele model, pooled OR=1.24, 95% CI: 1.08-1.44, P=0.004; for homozygous model, pooled OR=1.45, 95% CI: 1.14-1.84, P=0.003; for recessive model, pooled OR=1.29, 95% CI: 1.06-1.58, P=0.013; for dominant model, pooled OR=1.33, 95% CI: 1.08-1.65, P=0.009). Subgroup analyses by ethnicity and sensitivity analysis further pointed to associations, particularly in Asians. CONCLUSION This meta-analysis suggests that the A allele of CCND1 G870A polymorphism confers additional lung cancer risk.