[Study of proliferating cell nuclear antigen (PCNA), nucleolar organizer regions (NORs) and mitotic activity in epithelial ovarian tumors].

We investigated the proliferating cell activity of 121 epithelial ovarian tumors with formalin-fixed, paraffin-embedded tissue sections by means of the proliferating cell nuclear antigen (PCNA) labeling index, the mean number of nucleolar organizer regions (NORs) and mitotic activity. In the order of the malignant group (82 cases), the borderline-malignant group (19 cases) and the benign group (20 cases), the mean PCNA labeling index was 32.9, 12.8, 3.4(%), the mean number of NORs was 11.1, 5.8, 2.9 (/nucleus) and the mitotic index was 30.8, 8.0, 0.5 (/10HPF) and there was a significant difference (p < 0.001) between groups. There was a positive correlation (p < 0.001) among the PCNA labeling index, the mean number of NORs and the mitotic index. In 11 cases in the malignant group, the PCNA labeling index, the mean number of NORs and mitotic index in postchemotherapy were significantly lower than those in the prechemotherapy. It was suggested that the evaluation of proliferating cell activity in malignant cases was useful in investigating the malignant potential as well as the effect of chemotherapy.