IMMUNOHISTOCHEMICAL CHARACTERIZATION OF UNDIFFERENTIATED CARCINOMAS OF THE OVARY

Immunohistochemical characteristics of undifferentiated carcinomas of the ovary were examined using formalin-fixed, paraffin-embedded tissue s with an avidin-biotin staining approach. Eight cases were collected from the pathology files of our Institute from a total of 214 recorded malignant ovarian tumors. For immunostaining, antibodies reacting wit h epithelial membrane antigen (EMA), pankeratin, vimentin, CA 125, CA 19-9, carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), alpha-1 -antitrypsin (AT), epidermal growth factor receptor (EGFR), c-erbB-2, bcl-2 and p53 proteins were used. AH the cases examined were positive for EMA and pankeratin, specific markers for epithelial tumors, negati ve for the non-epithelial tumor marker, vimentin, and also positive fo r EGFR. Interestingly, only one case was positive for CA 125, despite it being one of the commonest reported indicators of ovarian cancer. C A 19-9 was positive in 7 eases, CEA in 5, AFP in 2, AT in 6 and c-erbB -2 protein in 4. Two cases were positive for p53 protein, and in 1 of these positive staining for bcl-2 was also observed. These results ind icate that the epithelial nature is well preserved in undifferentiated ovarian carcinomas, although consistently positive reactions were not observed within the cases for some antigens. They further clearly sho w that a negative signal for CA 125 can not be considered to exclude t he possibility of a primary ovarian tumor.