IMMUNOHISTOCHEMISTRY: MELAN-A

MELAN-A, PRODUCT OF MART-1 GENE, IS A DIFFERENTIATION ANTIGEN WHICH IS EXPRESSED IN 100% OF MELANOCYTES, MOST MELANOMAS, AND 50-60% OF MELANOMA CELL LINES. IT IS ONE OF THE MELANOMA ANTIGENS RECOGNIZED BY AUTOLOGOUS CYTOTOXIC T CELLS, AND AS AN ANTIGENIC TARGET FOR TUMOR INFILTRATING LYMPHOCYTES. THIS ANTIBODY ALSO STAINS MELAN-A IN NORMAL MELANOCYTES AND IN RETINA. IT DOES NOT STAIN NORMAL OR TUMOR TISSUES FROM NON-MELANOCYTE LINEAGES. THIS ANTIBODY STAINS POSITIVE IN THE CYTOPLASM OF MELANOCYTES AND OTHER POSITIVE CELLS. THIS IS A USEFUL MARKER FOR THE DIAGNOSIS OF MELANOCYTIC NEOPLASMS.