MC1R and melanoma: It has been shown that variants of pigmentation loci such as in ASIP, an MC1R receptor antagonist competing with the α-MSH/MC1R cascade and thus inhibiting the constitutive pigmentation, the melanogenic enzymes TYR and TYRP1 [113] or MATP/SLC45A2 (membrane-associated transporter protein/solute carrier family 45 member 2) involved in intracellular processing and trafficking of melanosomal proteins [114] are significantly associated with increased melanoma risk [113].