Ex vivo characterization of tumor-derived melanoma antigenencoding gene-specific CD8 1 cells in patientswith hepatocellular carcinoma

BACKGROUND/AIMS: Members of the melanoma antigen encoding gene family are expressed in tumors of different histological types but not in normal tissue. For this reason, they are attractive targets for cancer immunotherapy. METHODS: In the present study, we analyzed the expression of MAGE-1 and -3 genes in the hepatocellular carcinoma (HCC) tissue as well as frequency, phenotype and function of circulating and tumor infiltrating CD8+ cells specific for HLA-A1 and -A2 restricted epitopes of MAGE-1 and -3. RESULTS: Our study shows for the first time the presence of MAGE/tetramer+ CD8 cells in the tumor tissue of patients with HCC. These cells are able to recognize the MAGE-1 sequence 161-169 and the MAGE-3 sequence 271-279. In a patient with a particularly high frequency of MAGE-1 sequence 161-169-specific T cells, phenotypic and functional analysis was performed showing a phenotype of recently-primed CD8 cells (CD28+CD27+CD45RA-CCR7). CONCLUSIONS: The observation of a spontaneous in vivo priming of a MAGE-specific T cell response in patients with HCC and the high frequency of MAGE antigens expression in this tumor, makes this antigen a potential candidate for a MAGE-specific immunotherapy in hepatocellular carcinoma.