Growth potential of endometrial cancers assessed by a Ki-67 Ag/DNA dual-color flow-cytometric assay.

Ki-67 is a monoclonal antibody directed against a nuclear antigen present only in proliferating cells. To assess the growth potential of uterine endometrial cancer, the population of cells in proliferating cycle (%PC) was examined with Ki-67, using flow cytometry. The %PC of 27.18 +/- 12.00% in 22 endometrial cancers was significantly higher than the 14.5 +/- 5.94% found in 28 normal endometrial tissues. In premenopausal endometrial tissue, the %PC in the proliferatory phase was significantly higher than the %PC found in the secretory phase. In endometrial cancers, an increase of %PC was found in cases with deep myometrial invasion, and the %PC was elevated in groups containing histologically poorly differentiated types when compared to groups of well-differentiated and moderately differentiated types. Sorted cells reactive with Ki-67 antibody were large and had a high nuclear/cytoplasmic ratio. On the bases of these results, it was concluded that a Ki-67 Ag/DNA dual-color assay would be useful to examine the growth fraction in endometrial carcinoma and that an increased growth fraction was related to deep myometrial invasion or poorly differentiated types.