Unique Features of Melanoma Risk and Diagnosis in Red-Haired Populations.
Cutaneous melanoma is the most lethal skin cancer, and risk is strongly shaped by pigmentary phenotype. The red-hair color phenotype, marked by red hair, fair skin, freckling, and poor tanning, carries elevated melanoma risk driven largely by loss-of-function variants in the melanocortin 1 receptor gene (MC1R). This risk is not explained by reduced ultraviolet protection alone. Impaired MC1R signaling shifts melanogenesis from photoprotective eumelanin toward pheomelanin, a pigment associated with oxidative stress and partly ultraviolet-independent melanomagenesis. MC1R may also influence melanoma susceptibility through pigment-independent effects on DNA damage responses, repair signaling, and genomic stability. These mechanisms support investigation of MC1R genotype, visible phenotype, nevus burden, pigment chemistry, and imaging-derived lesion metrics as complementary tools for risk stratification. Diagnosis is also distinctive in this population. Amelanotic and hypomelanotic melanomas are associated with the red-hair color phenotype, and their low pigmentary contrast may delay recognition and contribute to diagnosis at a more advanced stage. This review integrates genetic, molecular, biomarker, diagnostic, and therapeutic literature specific to red-haired populations. We argue that elevated biological susceptibility and diagnostic difficulty compound one another, and we outline priorities for MC1R-informed surveillance, imaging adapted to pigment-poor disease, pharmacologic modulation of MC1R-related pathways, and prospective risk models integrating genotype, phenotype, nevus burden, pigment biology, and imaging.