Expression of tumor-rejection antigens in gynecologic cancers

Abstract

We recently reported the four tumor-rejection antigens (SART1259, SART2, SART3, and ART4) that possess tumor epitopes capable of inducing HLA-A2402-restricted cytotoxic T lymphocytes (CTLs) in cancer patients. This study investigated the expression of these tumor antigens in gynecologic cancers, including 33 ovarian cancers, 38 cervical cancers, and 40 endometrial cancers. SART1259 antigen was detected in 56%, 35%, and 30% of ovarian, cervical and endometrial cancers, while SART2 antigen was detected in 46%, 66%, and 30% of these cancers, respectively. Both SART3 and ART4 antigens were detectable in the majority of these gynecologic cancers tested. In contrast, none of these antigens was detectable in any of the normal ovarian and uterine tissues tested. Peripheral blood mononuclear cells (PBMCs) of HLA-A24+ patients with gynecologic cancers were found to produce significant levels of interferon-γ in response to HLA-A24+ SART3+ gynecologic cancer cells after having been stimulated three times in vitro with either SART3109-118 or SART3315-323 peptide. These PBMCs lysed HLA-A24+ SART3+ gynecologic cancer cells, but not HLA-A24- SART3+ gynecologic cancer cells or HLA-A24+ normal cells. Therefore, these four antigens and their peptides, including SART3 peptides, would be appropriate molecules for use in specific immunotherapy of HLA-A24+ gynecologic cancer patients.