Prostatic carcinoma: histological and immunohistological factors affecting prognosis.

Neuro-endocrine or paracrine cells of the human prostate and urethra have been identified by various methods, predominantly silver stains and immunocytochemistry. The incidence of neuro-endocrine differentiation in prostatic carcinoma has varied considerably from 10 to 100%, but has not been studied previously as an independent factor affecting prognosis. Nucleolar organiser regions (NORs) are loops of ribosomal RNA occurring in the nucleoli of cells which ultimately process RNA genes. NORs have been demonstrated by silver (Ag) staining techniques and have been studied in numerous malignant tumours. A pilot study from this laboratory has shown a distinct and significant difference in AgNOR staining between prostatic carcinoma and benign prostatic epithelial hyperplasia. A retrospective study was performed with at least 6 years' follow-up. This confirmed the presence of neuro-endocrine cells in more than half of the patients under investigation. A significant correlation between survival and the absence of neuro-endocrine cells was demonstrated. AgNOR staining was shown to be of no prognostic value.