Treatment Options for Melanoma of Gray Horses

All gray horses inherited a single gene mutation, S7X17(G), that alters melanocyte behavior to cause graying and propensities to develop vitiligo and melanoma. The coat color genes ASIP(a) and MC/R-E add risk such that relative likelihood of melanoma based on pregraying coat color is black > bay > chestnut. Melanomas begin at about 4 years. Locoregional control of melanoma masses depends on surgical removal and/or intralesional chemotherapy (possibly with adjunctive hyperthermia or electroporation). Systemic treatment is not evidence based but immunomodulators (cimetidine, levamisole) and vaccines can be tried.