ADJUVANT ROLE OF MIB1 INDEX IN DIFFERENTIATING SEROUS OVARIAN-TUMORS - PRELIMINARY-REPORT

Atypically proliferating serous tumors (APST) account for 15% of all o varian serous epithelial neoplasms. The differences between benign, bo rderline and malignant ovarian tumors is principally due to their cell ular proliferative potential. By means of MIB1 expression we could rec ognize differences in proliferation among serous ovarian tumors, overc oming interobserver variability. Thirty-three patients with serous ova rian tumors, treated at S. Raffaele Hospital University of Milan betwe en November. 1, 1992 and July 31, 1994 were used as study the populati on: 9 patients had serous cystoadenocarcinoma, 14 patients had APST an d 10 patients had serous cystoadenoma. Pathological slides of all the cases were reviewed and immunohistochemical analysis was performed on formalin fixed, paraffin wax embedded tissue Pearson's Chi-square test and Fisher's exact test were performed for statistical evaluation. Th e percentage of MIB1 positive neoplastic cells ranged from, 0% to 2.1% (median 0.45%; mean 0.69%) in cystoadenomas, 2.3% to 7% (median 2.9%; mean 3.98%) in APSTs and 4.7% to 20.3% (median 6.95%; mean 9.51%) in cystoadenocarcinomas (p<0.0001; F = 47.7). A High percentage expressio n of MIB1 in a serous tumor, initially diagnosed as APST, promoted a w ider sampling of the surgical specimen confirming the presence of a ca rcinomatous component. MIB1 index is reported as representative of cel lular proliferative potential The analysis of MIB 1 index provided val uable information in addition to that gained by conventional microscop ic study in all cases were diagnostic difficulties arose in assessing APST.