Nucleolar organizer regions: a potential prognostic factor in adenocarcinoma of the endometrium

Nucleolar organizer regions, which are evaluated using a silver stain for paraffin-embedded sections (AgNOR), can be used as a measurement of cellular proliferative activity. In the endometrium significant differences have been seen between benign and malignant lesions. To determine if AgNOR counts are of prognostic value in endometrial cancer, we examined 28 patients who developed recurrent disease after surgical stage Ib and Ic endometrial cancer and compared this group with a matched control group of patients who did not develop recurrence. The mean AgNOR number per cell was significantly higher in patients with recurrent disease (P = 0.001). Only five of these patients had values less than 4, whereas only three of the control group had values higher than 4. There was also a significant difference in the percentage of cells with more than 5 and more than 8 AgNORs (P = 0.001). After radiation therapy, the number of AgNORs per cell decreased. Recurrent tumors had higher AgNOR counts than the respective primary tumors. In conclusion, patients at increased risk for recurrent endometrial cancer can be identified by high AgNOR counts. Further evaluation of this parameter and comparison to other prognostic factors seems warranted.