KI67 ANTIGEN IMMUNOSTAINING (MIB-1 MONOCLONAL-ANTIBODY) IN SEROUS OVARIAN-TUMORS - INDEX OF PROLIFERATIVE ACTIVITY WITH PROGNOSTIC-SIGNIFICANCE

The purpose of this study was to evaluate the biological significance of Ki67 antigen expression in serous ovarian tumors, through the analy sis of MIB 1 monoclonal antibody reactivity in cystoadenomas, borderli ne tumors, and invasive cystoadenocarcinomas; the correlation between this index of cell proliferation and clinicopathologic parameters (FIG O stage and grade, and disease-free survival) was also investigated in invasive cystoadenocarcinomas. Fifty-four patients with serous ovaria n tumors, treated at the Institute of Gynecologic and Obstetrics, Anco na University, Italy, were used as study population; 10 women had sero us cystoadenoma, 16 women had serous borderline tumor, and 28 women ha d invasive cystoadenocarcinoma. The expression of primary tumor prolif eration related to Ki67 antigen was immunohistochemically evaluated by monoclonal MIB 1 antibody (Immunotech, Marseille Cedex, France) on mi crowave oven-processed formalin-fixed paraffin-embedded tissue. Compar ed to cystoadenomas and borderline tumors, the tissular Ki67 antigen i mmunostaining was significantly higher in cystoadenocarcinomas, with t he highest values in architectural grade 2 and 3 neoplasms (P < 0.001) . Within the cystoadenocarcinomas, a relationship was observed between the measured proliferation index and disease FIGO stage, but it was n ot significant (P = 0.92). However, patients who recurred and/or had d isease progression presented a primitive neoplasm with significantly h igher expression of Ki67 antigen than that of patients with disease-fr ee survival (P = 0.01). A significant relationship was observed betwee n the Ki67 index and disease-free survival, independent of histologic grade and stage, evaluated by Cox hazards analysis (P = 0.02). The pro liferation index detected by Ki67 antigen immunostaining may represent an indicator of aggressiveness in serous ovarian tumors and an additi onally useful prognostic factor in cystoadenocarcinomas, probably inde pendent of and apparently more significant than the tumor architectura l grade and the disease FIGO stage. (C) 1995 Academic Press, Inc.