Ki 67 expression in 35 borderline ovarian tumours: relations with clinicopathologic parameters and ploidy.

Abstract

Objective: To test the diagnostic and prognostic interest of Ki 67 expression and DNA ploidy in ovarian tumours. Methods: The reactivity of tumour cells with the monoclonal antibody MIB 1 against Ki 67, was assessed by an indirect immunoperoxidase staining technique applied to 25 benign, 35 borderline and 20 malignant tumours of the ovary. In each cases, ploidy was analyzed by DNA flow cytometry. Results: Ki 67 immunopositivity was detected in three benign tumours (12%), 14 borderline tumours (40%) and 14 ovarian carcinomas (70%). The mean and standard deviation of Ki 67 positive cells in benign, borderline and malignant tumours were: 1%±8, 5%±9.6 and 44.5%±31 respectively. A difference in Ki 67 immunostaining was found between carcinomas and benign tumours (P<0.0001), and between borderline and carcinomas (P=0.001) but not between benign and borderline tumours. Evaluable DNA histograms from flow cytometry were generated in 77 cases (96.2%) of ovarian tumours. All 25 benigns, 97.1% of 35 borderline and 44.5% of 20 malignant ovarian tumours were diploid. A difference was found between borderline and carcinomas (P=0.001), but not between borderline and benign tumours. Conclusion: Ki 67 labelling was correlated with neither histologic and prognostic parameters, nor with survival, nor with DNA ploidy in borderline ovarian tumours.