A review of neuroendocrine features in breast carcinomas is presented and markers for neuroendocrine cells are discussed. Immunostaining for neuron specific enolase is the best screening marker for neuroendocrine cells in breast carcinomas, but immunoreactivity for hormones is not present in all neuron specific enolase (NSE) positive cases. Normal myoepithelial cells are also NSE positive. Thirty per cent of breast carcinomas are NSE positive. Biochemical demonstration of ACTH, PTH and calcitonin, and immunohistochemical demonstration of ACTH, bombesin, serotonin, prolactin, gastrin, VIP, leu-enkephalin, pancreatic polypeptide, beta-endorphin and sub P has been reported in breast carcinomas. Neuroendocrine cells have not been convincingly demonstrated in the normal breast or in benign breast lesions.