Abstract
In a hospital-based case-control study of 805 non-Hispanic whites with cutaneous melanoma and 841 cancer-free age-, sex- and ethnicity-matched control subjects, 3 VDR polymorphisms (i.e., TaqI, BsmI and FokI) were genotyped using blood samples collected between 1994 and 2006. We tested the hypothesis that the haplotypes and combined genotypes of these polymorphisms were associated with melanoma risk by interacting with known risk factors. Haplotypes t-B-F (adjusted odds ratio [OR], 0.52; 95% confidence interval [CI], 0.34-0.80) and t-B-f (adjusted OR, 0.51; CI, 0.27-0.94) were associated with a reduced risk when compared to T-b-f. The combined genotypes Tt+tt/Bb+BB/Ff+ff (adjusted OR, 0.69; CI, 0.52, 0.90) and Tt+tt/Bb+BB/FF (adjusted OR, 0.58; CI, 0.43, 0.78) were also associated with reduced risk, whereas the combined genotype TT/Bb+BB/Ff+ff genotype (adjusted OR, 2.35; CI, 1.13, 4.98) was associated with increased risk when compared to TT/bb/Ff+ff genotypes. On multivariate analysis, only the TaqI polymorphism was an independent risk factor, while the FokI polymorphism interacted with skin color (p = 0.029), moles (p = 0.017) and first-degree relatives with any cancer (p = 0.013) in modifying risk. Together, these findings suggest that VDR polymorphisms may directly affect or modify the risk associated with known melanoma risk factors. Larger, population-based studies are needed to replicate our findings.