A protein found on normal melanocytes (cells that make the pigment melanin) in the skin and in the retina. It is also found on most melanomas (cancers that begin in melanocytes). Vaccines using pieces of the Melan-A protein are being studied for their ability to boost the immune response to cancer cells in patients with melanoma. Also called MART-1 antigen and Melanoma Antigen Recognized by T cells 1.