Objective.To determine the apoptotic and proliferative activities in various ovarian epithelial tumors.Methods.Formalin-fixed

paraffin-embedded tissues of 86ovarian epithelial tu mors

including 52adenocarcino-mas

23borderline tumors and 11cystadenomas

were retrieved.Apoptoti c（AI ）and proliferative（PI ）index were estimated using the monoclonal antibodies:M30

Ki-67and Ki-S1in t hese tumors.Quantitative assess-ment of AI and PI was estimated by calc ulating the percentage of positive c ells among no less than 1000tumor cells.Results.Statistically significant differe nce in AI was found between benign and borderline tumors or carcino-mas（P=0.028

0.001

respectively）.Significant differences in PI

as a ssessed by both Ki-67and topo IIα

were demonstrated between carcinom as and benign or borderline tumors（both P<0.001）.Benign tumors had both low PI and AI;borderline tumors had lower PI but higher AI

while aden ocarcinomas had both high prolifera-tive and high apoptotic rates.Among borderline tumors

serous tumors had significantly lower AI and higher PI than mucinous ones.Conclusions.The results suggest that apoptotic a nd proliferative activities play im portant roles in the pathogene-sis and development of ovarian borderline and malignant tumors.The high apoptotic rate in borderline tumor m ay explain its relatively indolent beh avior while the high proliferative r ate in carcinomas tends to explain its aggres-sive behavior.