Silver staining of nucleolar organizer regions in prostatic lesions

Variations in the number of silver-stained nucleolar organizer region-associated proteins (AgNORs) were studied in paraffin sections of 42 benign prostatic lesions, comprising four cases of granulomatous prostatitis, five of squamous or transitional metaplasia, eight of atypical and 25 of regular hyperplasia, and 37 of prostatic adenocarcinoma, with their metastases. There was a significant difference between the mean AgNOR counts of the benign and malignant prostatic lesions (1.58 +/- 0.26 v. 4.34 +/- 1.53; P less than 0.01). The mean AgNOR counts significantly increased with increasing Gleason's grade (P less than 0.01) and clinical stage (P less than 0.05) of the tumours. AgNOR counting may contribute to the conventional diagnostic and prognostic indices of cancer of the prostate.