Nuclear DNA content of borderline tumors of the ovary: correlation with histology and significance for prognosis.

Scanning-DNA cytophotometry was applied to Feulgen stained sections of 22 borderline tumors of the ovary (BOT). The DNA content was related to conventional histology. In 11 cases clinical follow up for more than 5 years was available. The DNA measurements disclosed two subgroups in the group of BOT. One showed a nuclear DNA content not exceeding tetraploidy (4c) indicating proliferative activity without malignant change and a second one exhibited DNA values higher than 4c indicating malignant transformation. Correlation of histological evaluation with the DNA content revealed a good agreement in 15 cases. However, a discrepancy was found in 7 cases: either the histological evaluation aroused suspicion for malignant potential but the histogram showed DNA values not higher than 4c (n = 4), or histology showed well differentiated lesions with an atypical histogram (n = 3). Clinical monitoring revealed no recurrence or tumor spread in all but one case of the group of lesions with DNA values up to 4c, whereas in the group with atypical DNA histograms (DNA values greater than 4c) relapse appeared in 6 out of 7 cases. The results suggest that DNA analysis has prognostic significance for BOT.