MELAN-A MART-1 ANTIGEN EXPRESSION IN CUTANEOUS AND OCULAR MELANOMAS/

The human immune repertoire appears to be capable of recognizing norma l antigens expressed by tumor cells. Among these antigens, those of di fferentiation, characterized by a restricted tissue expression, could be of clinical interest since they may represent a target for immunoth erapeutic protocols. In this context we have evaluated, in benign and malignant lesions of the melanocytic lineage, the expression of the Me lan-A/MART-1 antigen, which has been shown to be recognized by T cells , of HLA-A2 melanoma patients. The immunohistochemical analysis conduc ted with a Melan-A/MART-1 monoclonal antibody demonstrated that the an tigen expression does not correlate with transformation or tumor progr ession. At variable levels Melan-A/MART-1, differently from other diff erentiation antigens, is homogeneously expressed by multiple autologou s metastases and by melanoma metastases at different body sites. This tissue distribution adds further biological support to the ongoing use of Melan-A/MART-1-related peptides in active immunotherapy.