[Histochemical characterization of endometrial proliferation using AgNOR (nucleolus organizer region)]

Nucleolar organizer regions (NORs) are loops of DNA that transcribe to ribosomal RNA. We used histochemical staining of NORs for 78 sections of endometrial tissue, obtained either from curettage or from hysterectomy specimens (normal endometrium 14, simple hyperplasia 10, complex hyperplasia 18, atypical hyperplasia 8 and adenocarcinoma 28). There was a significant positive correlation between mean AgNOR counts and the degree of hyperplasia. In adenocarcinoma, no significant difference was found between AgNOR counts in tissues of different histologic grades. Our study suggests that AgNOR counts are reliable markers of endometrial proliferation and allow a clear distinction between benign, premalignant and malignant epithelial changes.