DNA ploidy level and cell cycle distribution in ovarian cancer: relation to histopathological features of the tumor.

We analyzed nuclear DNA content and S-phase fraction (SPF) from 157 paraffin-embedded ovarian tumors by flow cytometry and compared the results with the clinicopathological features of the tumors. DNA aneuploidy was more common and mean SPF was higher in advanced than in early-stage tumors (p less than 0.001). DNA aneuploidy was most often (75%) observed in undifferentiated tumors (World Health Organization classification) and most seldom (30%) in mucinous carcinomas. Mean SPF values ranged from 17.7% in undifferentiated carcinomas to 11.1% in mucinous carcinomas. DNA flow cytometric results correlated better with nuclear than with histological tumor grade. The proportion of DNA-aneuploid tumors increased from 30% in nuclear grade I to 93% in nuclear grade III, and mean SPF increased from 9.9 to 20.2% (p less than 0.001). DNA ploidy and SPF were independently associated with both stage and nuclear grade of the tumor, whereas the differences between the histopathological tumor types virtually disappeared when the groups were adjusted for nuclear grade. On the basis of these clinicopathological correlations, it appears that DNA ploidy and SPF reflect the malignant potential of ovarian tumors and thus complement the routine histopathological evaluation.