Genomic Risk Score for Melanoma in a Prospective Study of Older Individuals.

BACKGROUND Recent genome-wide association meta-analysis for melanoma doubled the number of previously identified variants. We assessed the performance of an updated polygenic risk score (PRS) in a population of older individuals, where melanoma incidence and cumulative ultraviolet radiation exposure is greatest. METHODS We assessed a PRS for cutaneous melanoma comprising 55 variants in a prospective study of 12,712 individuals in the ASPirin in Reducing Events in the Elderly trial. We evaluated incident melanomas diagnosed during the trial and prevalent melanomas diagnosed pre-enrolment (self-reported). Multivariable models examined associations between PRS as a continuous variable (per standard deviation [SD]), and categorical (low-risk [0-20%], medium-risk [21-80%], high-risk [81-100%] groups) with incident melanoma. Logistic regression examined the association between PRS and prevalent melanoma. RESULTS At baseline, mean participant age was 75 years; 55.0% were female, and 528 (4.2%) had prevalent melanomas. During follow-up (median = 4.7 years), 120 (1.0%) incident cutaneous melanomas occurred, 98 of which were in participants with no history. PRS was associated with incident melanoma (hazard ratio = 1.46 per SD, 95% confidence interval [CI] = 1.20-1.77) and prevalent melanoma (odds ratio [OR]=1.55 per SD, 95% CI = 1.42-1.69). Participants in the highest-risk PRS group had increased risk compared to the low-risk group for incident (OR = 2.51, 95% CI = 1.28-4.92) and prevalent (OR = 3.66, 95% CI = 2.69-5.05). When stratifying by sex, only males had an association between the PRS and incident melanoma, whereas both sexes had an association between the PRS and prevalent melanoma. CONCLUSION A genomic risk score is associated with melanoma risk in older individuals, and may contribute to targeted surveillance.