C-erbB-2 protein and neuroendocrine expression in intraductal carcinomas of the breast.

A total of 52 intraductal carcinomas were classified according to nuclear size and histologic subtype and immunostained for neuron-specific enolase (NSE) and c-erbB-2 oncoprotein. Eleven out of 13 cases of the large cell comedo variant of intraductal carcinoma exhibited strong c-erbB-2 protein immunoreactivity, while only one was NSE positive. Nineteen out of 23 intraductal carcinomas of small cell type exhibited NSE immunoreactivity. None of these was c-erbB-2 protein positive. Some 72% of NSE positive cases were also immunoreactive for other neuroendocrine screening markers and/or hormones. We conclude that there is an inverse relationship between NSE immunoreactivity and c-erbB-2 protein expression in intraductal carcinomas.