Cyclin D1 gene polymorphism as a risk factor for oral premalignant lesions

Background: Deregulation of cell cycle plays an important role in tumorigenesis. Cyclin D1 gene (CCND1) is a key regulator of the G₁ phase of the cell cycle. Methods: In this case-control study of 115 oral premalignant lesion (OPL) patients and 230 controls, we genotyped the CCND1 single nucleotide polymorphism (SNP) at the exon 4 splice site (G870A) and determined the association of this SNP with the risk of developing OPLs. Results: We found significant associations between the heterozygous variant allele (GA), the homozygous variant allele (AA) and OPL risk, with adjusted odds ratios (ORs) of 1.91 [95% confidenc interval (CI), 1.05-3.48] and 2.38 (95% CI, 1.16-4.87), respectively. The OR for individuals with at least one variant allele was 2.04 (95% CI, 1.15-3.60). When further stratified analyses were performed, the increased risk was more evident in younger individuals (OR = 2.82; 95% CI, 1.32-6.02), in men (OR = 2.97; 95%CI, 1.31-6.71) and in never smokers (OR = 2.92; 95% CI, 1.09-7.82). Finally, we found joint effects between the variant alleles and the smoking status. Using never smokers with the wild-type (GG) genotypes as the reference group, the ORs for never smokers with the variant genotypes (G/A + A/A), smokers with the G/G genotype and smokers with the G/A + A/A genotypes were 2.92 (1.09-7.82), 3.95 (1.36-11.5) and 7.01 (2.68-18.4), respectively. Conclusion: Our results suggest that the CCND1 G870A SNP may contribute to genetic susceptibility to OPLs and involve in oral cancer development.