Skin toxicities, an on-target reaction to gp100-expressing melanocytes, were frequent—rash and pruritus, each 83%, dry skin 64%, pigment or erythema changes 57%—yet two-thirds were grade 1–2, presented within the first few doses, and responded to antihistamines or topical corticosteroids, with no cases of Stevens–Johnson syndrome or toxic epidermal necrolysis. This evidence concerns the gene PMEL and Erythema.