XRCC6P5 and mucosal melanoma: Primary malignant melanoma rarely develops on mucosal membranes, and its occurrence in the respiratory, digestive, and urogenital systems is explained by the presence of melanocytes in the mucosal membranes of these tissues.6 Although p53 mutations, loss of heterozygosity, and expression of DNA repair protein have been documented, the etiology of mucosal melanoma remains unclear.7-9