IDENTIFICATION OF A MEIOTICALLY EXPRESSED CARBOHYDRATE ANTIGEN IN OVARIAN-CARCINOMA .1. IMMUNOHISTOCHEMICAL LOCALIZATION

A monoclonal antibody developed against a meiotically expressed porcin e oocyte carbohydrate antigen has been shown to recognize an antigen i n ovarian surface epithelial cells. Immunohistochemical studies of ova ries demonstrated that this antigen is present in the ovarian surface epithelia (OSE) of numerous mammalian species, including the nonhuman primate and the human (1). Although most of the ovarian surface epithe lial cells are lost during aging in the human, a few cells may remain in ovarian crypts. In view of theories that most ovarian carcinomas ar e derived from the OSE cells in aging women, the PSI antibody has been used to evaluate ovarian tumors using immunocytochemistry to detect t he PSI antigen in paraffin embedded pathology tissues. The present stu dy found that the PSI antigen, is abundant in a number of malignant ov arian tumors, but is not expressed in a non-malignant Brenner's (ovari an) tumor or granulosa cell tumors. This antibody therefore appears to have great potential for the histopathological and immunochemical ana lysis of ovarian tumors.