Expression of MAGE-antigens in normal tissues and cancer

The human MAGE gene family encodes products that can be recognized by autol ogous cytotoxic T cells. Because MACE genes are silent in most normal tissu es except testis but are activated in a variety of neoplastic lesions, MAGE antigens represent ideal targets for immunotherapy. Current knowledge of M AGE gene expression is based primarily on mRNA typing and relatively little is known about MAGE protein expression. Monoclonal antibody (MAb) 57B, ori ginally thought to be specific for MAGE-3, but now known to be reactive wit h other MAGE components, was used in the present study to analyze MACE expr ession in a panel of normal and malignant tissues. In tests with a wide ran ge of normal tissues, only spermatogenic cells of testis were reactive with 57B, In tumor tissues, significant immunoreactivity was observed in malign ant melanomas and carcinomas of the lung, head and neck as well as urinary bladder. No 57B reactivity was seen with colorectal, prostatic or renal cel l carcinomas. Lipo- and myosarcomas, as well as malignant fibrous histiocyt oma (MFH), were negative, but synovial sarcomas showed intense immunoreacti vity, A subset of seminomas was also strongly reactive with 57B, Tumor spec imens showed great variability in the number of tumor cells showing 57B rea ctivity, with some tumors showing only small isolated clusters of positive cells to other tumors with uniform staining throughout the tumor. Int. J, C ancer 85:460-465, 2000, (C) 2000 Wiley-Liss, Inc.