BREAST AND OVARIAN CANCER-SPECIFIC CYTOTOXIC T-LYMPHOCYTES RECOGNIZE THE SAME HER2/NEU-DERIVED PEPTIDE

The identification of antigenic peptides presented on the tumor cell surface by HLA class I molecules and recognized by tumor-specific cytotoxic T lymphocytes may lead to a peptide vaccine capable of inducing protective cellular immunity. We demonstrate that both HLA-A2-restricted breast and ovarian tumor-specific cytotoxic T lymphocytes recognize shared antigenic peptides. At least one of these peptides is derived from the oncogene product of HER2/neu, which is overexpressed in 30-40% of all breast and ovarian cancers. T cells sensitized against this nine-amino acid sequence demonstrate significant recognition of HLA-A2(+), HER2/neu(+) tumors. Since 50% of ther tumor-cell population is HLA-A2(+) and many different tumors express HER2/neu, this peptide may be widely recognized and have many clinical applications.