Immunohistochemical characterization of a monoclonal antibody detecting an endometrioid ovarian cancer-associated antigen.

Murine monoclonal antibody FEN-1 was derived by immunizing Balb/c mice with an affinity-purified endometrioid ovarian cancer-associated antigen recovered from ascites-derived immune complexes. Splenic lymphocytes from the immunized mouse were fused with the myeloma cells SP2/0-AG14 in the presence of PEG 1500. The hybrid cultures were screened for production of immunoglobulins reactive with an extract preparation of an endometrioid ovarian tumor by enzyme-linked immunosorbent assay and flow cytometry. One of the hybrids secretes a monoclonal antibody of the IgG3 subtype designated FEN-1, which reacts with 100% of endometrioid ovarian cancer containing adenoacanthoma by indirect immunoperoxidase on paraffin-embedded tissue. No detectable levels of antigen were found in squamous metaplasia associated with nonendometrioid tumors, and no reactivity occurred against endometrial adenocarcinomas, endometriosis, or normal ovary and endometrium. The antibody does not cross-react with mucinous tumors, nonepithelial tumors of the ovary, or gastrointestinal tissue. This antibody may be used as an aid in the diagnosis of nonmucinous ovarian carcinomas by immunohistology.