Neu (c-erbB-2), a tumor marker in carcinoma of the female breast.

The c-erbB-2 oncogene encodes a transmembrane phosphoglycoprotein. This molecule appears to be a growth factor receptor in the family of tyrosine kinase growth factor receptors; however, its ligand has not yet been identified. Amplification and/or overexpression of c-erbB-2 in breast adenocarcinomas occurs frequently and its occurrence implies a more advanced malignancy. This functional tumor marker is readily identified by appropriate DNA and antibody probes. The large external domain of the c-erbB-2 gene product is a promising target for immunodiagnostic and immunotherapeutic modalities.