Nucleolar organizer regions in benign and malignant prostatic disease

A modified silver stain technique for visualizing nucleolar organizer regions (AgNOR counting) was applied to 24 benign and 23 malignant prostatic biopsies. Marked inter‐observer variation was found, particularly in sections with high AgNOR counts. After averaging the AgNOR counts of both observers, there was no significant difference in counts between the benign and the malignant biopsies. The AgNOR count appeared to be increased in tumours up to Gleason histological grade 6, but not in tumours of Gleason histological grade 7 or more.