Selective immunolabeling of early gestational cytotrophoblast and its neoplastic counterpart by the monoclonal antibody Ber-EP4.

This report presents preliminary observations on the distribution of an epithelial surface antigen in human trophoblastic cells studied with the monoclonal antibody Ber-EP4 by means of an immunoperoxidase technique. Three cases of gestational choriocarcinoma and 20 cases of both villous and extravillous trophoblast, including one complete hydatidiform mole and one exaggerated placental site, were examined with a panel of monoclonal antibodies against epithelial antigen (Ber-EP4), cytokeratin (AE1 and AE3), vimentin (VIM), carcinoembryonic antigen (CEA) and epithelial membrane antigen (EMA), as well as with polyclonal antibodies against the beta subunit of human chorionic gonadotropin (hCG), human placental lactogen (hPL) and placental alkaline phosphatase (P1AP). While, as anticipated, all currently defined trophoblastic cell lines expressed low molecular weight cytokeratin only first trimester cytotrophoblastic cells and their neoplastic counterpart were found to possess the epithelial antigen detected by Ber-EP4. This distinctive property of the cytotrophoblast declined rapidly after eight weeks of gestational age but persisted in second trimester molar tissue and was prominently displayed in choriocarcinoma. By identifying the presence of cytotrophoblastic cell lines in malignancy more reliably than can be achieved with conventional panels of hCG, hPL and P1AP, Ber-EP4 has potential diagnostic utility in gestational trophoblastic disease. Our findings also suggest that the monoclonal anti-CEA antibody may be helpful in distinguishing between syncytiotrophoblastic cells and non-reactive multinucleate cells of the intermediate trophoblast.

Immunohistochemical analysis for desmin in normal and neoplastic ovarian stromal tissue.

Ovarian stroma contains cells with the ultrastructural features of smooth-muscle cells. The purpose of this study was to analyze normal ovaries, ovarian stromal tumors (fibroma/thecomata and granulosa cell tumors), and ovarian leiomyomata for desmin reactivity. Groups of ovarian stromal cells that expressed desmin were noted in six of six normal ovaries. Desmin was also detected in two of six fibroma/thecomata and two of two ovarian leiomyomata. The number of tumor cells with detectable desmin was much greater in the leiomyomata. Desmin was not detected in any of six granulosa cell tumors. We conclude that stromal cells with an immunohistochemical feature of smooth-muscle cells are routinely found in normal ovaries. This study demonstrates the usefulness of immunohistochemistry in corroborating the diagnosis of ovarian leiomyomata, although desmin positivity per se is not diagnostic of ovarian leiomyomata, and also raises the possibility that some ovarian leiomyomata may be derived from stromal cells.