Melan-A is a melanocyte differentiation antigen,recognized by autologous cytotoxic T lymphocytes. Melan-A is also called MART-1 (melanoma antigen recognized by T cells). The Melan-A/MART-1 gene encodes this protein,20-22 kDa,associated with endoplasmic reticulum and melanosomes. The function of the protein is unknown. Melan-A,isolated as a melanoma-specific antigen,is a transmembrane protein,which is expressed in skin,retina and the majority of cultured melanocytes as well as in melanomas. Melan A is expressed in more than 85% of melanomas.