Immunologic characterization of tumor markers in human ovarian cancer cell lines.

OBJECTIVE: The purpose of this study was to evaluate the expression of a novel autologous ovarian tumor-associated antigen in eight human ovarian tumor cell lines compared with other ovarian tumor markers and products of oncogenes.
METHODS: Autologous antibodies were eluted from human ovarian tumor-membrane fragments purified in our laboratory. These antibodies react with autologous ovarian tumor-associated antigens (AOTA) and have a high degree of specificity for human ovarian tumors. They do not bind to normal ovarian or nonovarian tissues, or to nonovarian neoplastic tissues. We evaluated eight human ovarian adenocarcinoma cell lines (2008, 2774, Caov-3, OVCAR-3, PA-1, SW 626, UCI 101, and UCI 107) by indirect immunofluorescence to determine the expression of AOTA relative to the ovarian cancer tumor marker CA 125 and the products of selected oncogenes (p 53, c-neu, and c-myc).
RESULTS: The patterns and intensities of immunofluorescence correlated most closely between AOTA and c-neu. For example, AOTA and c-neu were detected in all eight cell lines and displayed very strong cytoplasmic fluorescence on cell lines 2774, UCI 101, and UCI 107. CA 125 was present in the cytoplasm of four of eight cell lines. A tumor suppressor gene product, p53, exhibited a nuclear staining pattern in six of eight cell lines.
CONCLUSIONS: These data suggest that AOTA and the products of the c-neu oncogene may share certain epitopes. Current studies are underway to increase our understanding of the humoral response to ovarian cancer and the possible relationship to the expression of tumor oncogene products. Further characterization of AOTA will be necessary before early diagnostic tests can be developed.