c-erbB-1 (epidermal growth factor receptor) and c-erbB-2 oncoprotein have common tyrosine kinase activities, and alteration in their expression has been defined in various visceral tumors. However, relatively little is known about their expression in skin tumors.

Our aim was to evaluate the distribution and expression pattern of c-erbB-1 and c-erbB-2 in skin neoplasms.

We have undertaken an immunohistochemical survey of c-erbB-1 and c-erbB-2 in the tissue specimens of keratoacanthoma (KA), actinic keratosis (AK), squamous cell carcinoma (SCC) and basal cell carcinoma (BCC).

Membranous c-erbB-1 expression had a tendency to be down-regulated in some specimens of SCC and dysplastic portions of AK. In invasive lesions of SCC, we observed increased cytoplasmic accumulation of c-erbB-1. Most specimens of BCC showed rather decreased expression of c-erbB-1 compared with other skin tumors. c-erbB-2 oncoprotein showed strong cytoplasmic staining in SCC, especially in the invasive tumor mass, and in some deeply dysplastic or hyperplastic portions of AK, though the difference of intensity was not striking between tumors. BCC revealed relatively weaker expression of c-erbB-2 than other skin tumors, which was similar in pattern to c-erbB-1.

The expression patterns of c-erbB-1 and c-erbB-2 are altered in various skin neoplasms, and seem to be related to the dysplastic status or differentiation level of tumor cells.