Neuroendocrine (NE) cells are present in both benign and malignant human prostate. However, their function is poorly understood, mainly due to the lack of suitable experimental models. The nerve growth factor-beta (NGF-beta) promotes the rat pheochromocytoma cell line PC-12 to differentiate into neuronal like cells. We have studied the effect of NGF-beta on four human prostate cancer cell lines, LNCaP, DU-145, PC-3, and TSU-pr1. NGF-beta stimulates the growth rate in all these cell lines, but does not induce a neuronal phenotype. NE tumour markers (chromogranin A [CgA] and chromogranin B[CgB]) could not be demonstrated by immunocytochemistry (CgA and CgB), Northern blotting (CgA), or ELISA techniques (CgA), neither in control nor in NGF-beta stimulated cells. Consequently, other experimental models have to be sought in the study of NE cells in the human prostate.