Expression of epithelial cancer-related antigens in hematologic malignancies applicable for peptide-based...

Recent advances in tumor immunology have resulted in identification of many epithelial cancer-related antigens and peptides applicable to specific immunotherapy. The authors investigated whether these peptides, which are being studied clinically, could be appropriate target molecules for treatment of patients with hematologic malignancies. The majority of hematologic malignant cells studied expressed five different epithelial cancer-related antigens. Cytotoxic T lymphocyte (CTL) precursors reactive to these antigen-derived peptides were detected in peripheral blood mononuclear cells (PBMCs) of the majority of HLA-A24 patients, and the mean number of peptides recognized by CTL precursors was 2.4 per patient, ranging from 0 to 8 among the 10 peptides tested. These peptide-stimulated PBMCs exhibited HLA-A24-restricted cytotoxic activity against hematologic malignant cells but not against blastoid T cells. More importantly, these peptide-stimulated PBMCs exhibited cytotoxicity against freshly prepared autologous malignant cells in an HLA-A24-restricted manner. These results may provide a scientific basis for the use of these peptides from epithelial cancer-related antigens in specific immunotherapy for patients with hematologic malignancies.