Nucleolar organizer regions in differentiated preneoplastic and neoplastic endometrial lesions.

The aim of the study was the quantitative assessment of nucleolar organizer regions (NORs) in the cells of preneoplastic and neoplastic endometrial lesions. Retrospective analysis included tissue material obtained from 87 patients with simple and complex hyperplasia with or without atypia and well-differentiated stage-I endometrial adenocarcinoma. Sections were made from routine paraffin blocks and stained with AgNO3. The mean number of AgNORs per cell was determined. The results obtained indicate that the evaluation of proliferative activity of cells expressed by AgNOR count can help in the distinction between atypical hyperplasia and well-differentiated adenocarcinoma, and thus can serve as a useful pathological criterion.