DETERMINATION OF PROLIFERATION INDEX IN ADVANCED OVARIAN-CANCER USINGQUANTITATIVE IMAGE-ANALYSIS

It has been shown that the monoclonal antibody Ki-67 reacts with a nuc lear antigen that is expressed only by proliferating cells. The feasib ility of using image analysis to quantitate Ki-67 staining (proliferat ion index [PI]) of epithelial ovarian cancers was investigated. The PI was determined in 50 advanced-stage primary ovarian cancers. Frozen s ections were immunostained with the Ki-67 monoclonal antibody, and the PI was calculated using static image analysis. Among 35 stage III ova rian carcinomas, the median PI was 8.9%, compared with 17.7% in 15 sta ge IV cancers (P = 0.06). There was no relationship between PI and his tologic grade. The median survival time of 32 patients whose cancers h ad a high Ki-67 expression (greater-than-or-equal-to 7.5%) was 16.8 mo nths, which differed significantly (P<0.01) from the median survival o f 31.5 months observed in patients whose tumors demonstrated low Ki-67 expression (<7.5%). Quantitative image analysis of Ki-67-stained fres h-frozen ovarian cancers may provide useful prognostic information. Fu rther studies are warranted to investigate the relationship between Ki -67 expression and other known clinicopathologic and genetic features of ovarian cancer.