IMMUNOHISTOCHEMICAL DETECTION OF MAGE TUMOR-ASSOCIATED ANTIGENS IN ESOPHAGEAL SQUAMOUS-CELL CARCINOMA

Genes of the MAGE family encode tumor-specific antigens recognized by cytotoxic T-lymphocytes in a variety of neoplasms. We investigated the protein expression of these antigens as related to the gene expressio n, in esophageal squamous cell carcinoma by using monoclonal antibodie s recognizing MAGE gene products. Esophageal squamous cell carcinomas were found to express both MAGE-1 (4 out of 15 samples) and MAGE-3 (7 out of 15 samples) genes, by RT-PCR. Immunoblotting revealed MAGE-1 an d MAGE-3 gene products in 2 and 6 out of 15 samples, respectively. Imm unohistochemistry performed on 12 samples showed MAGE-1 protein expres sion, limited to single tumor cells, in 2 cases. MAGE-3 gene product w as detectable in 7 cases: in 5 of them over 50% of neoplastic cells we re positive. Considering the high percentages of tumor cells expressin g MAGE-3 antigen, the use of epitope-based vaccines could be envisaged in patients displaying appropriate HLA-class I phenotype.