Sinclair swine display cutaneous melanoma lesions and develop a generalized depigmentation subsequent to tumor regression. Sinclair swine represent a valuable animal model to study the factors influencing the development of melanoma and also the factors which lead to the development of vitiligo. Therefore, information obtained in studies of Sinclair swine should facilitate our understanding of the mechanisms by which melanoma and vitiligo develop and provide us with possible therapeutic treatments for these human diseases.