The androgen receptor status of neuroendocrine cells in human benign and malignant prostatic tissue

Neuroendocrine (NE) cells containing neurosecretory granules, rich in various peptide hormones and biogenic amines, are components of the human prostate epithelium and prostatic adenocarcinomas. Neuroendocrine differentiation in prostatic adenocarcinomas has been associated with a poor prognosis and, following androgen withdrawal therapy, tumor cell populations have been observed to become enriched with NE cells. We assessed androgen receptor (AR) expression in NE cells in benign and malignant prostatic tissue using double-labeling immunocytochemistry with validated monoclonal antibodies to the AR and to chromogranin A (a generic NE marker). Neuroendocrine cells in benign and malignant prostatic tissue generally showed nuclear staining with AR. Some distinct AR-negative nuclei were observed in normal NE cells. In prostatic adenocarcinomas with extensive NE differentiation, a subpopulation of AR-negative NE cells was demonstrated. In conclusion, benign and malignant prostatic tissue contain both AR-positive and AR-negative NE cells that may have significance in regards to androgen-independent tumor growth and tumor progression.