MC1R, ASIP, TYR, and TYRP1 gene variants in a population-based series of multiple primary melanomas.

Allelic variants of the low-penetrance melanoma gene MC1R increase the risk of both melanoma and non-melanoma skin cancer. Common variants of the genes ASIP, TYR, and TYRP1, which regulate the melanogenic pathway, have also been shown to associate with melanoma. In this population-based study, we investigated SNPs of MC1R, ASIP, TYR, and TYRP1 as risk factors for development of multiple primary melanomas (MPM) in 388 Norwegian cases. The MPM patients had a significantly higher likelihood of carrying any MC1R variant than the control group of 420 blood donors [86.8 vs. 78.3%, OR = 1.73, and confidence intervals (CI) 1.18-2.52]. When MC1R variants were analyzed individually, Asp84Glu and Arg151Cys were significantly more frequent among the MPM cases than among the controls (OR = 5.77, CI 1.97-16.90, and OR = 1.80, CI 1.36-2.37, respectively). In addition, there was an allele dose-dependent increase in MPM risk for carriers of red hair color (RHC) MC1R variants. The AH haplotype of ASIP was also a significant risk factor for MPM development (OR = 1.72 and CI 1.12-2.49), whereas no association was observed for previously reported risk variants of the TYR and TYRP1 genes. In summary, by using a population-based material of high-risk melanoma cases, we demonstrate a significant effect of both MC1R RHC variants and an ASIP haplotype, but could not replicate an association with postulated risk SNPs of TYR and TYRP1.