HER-2 (p185 ERBB2, C-erb B2, NEU-protooncogene )

The HER-2 gene product is a 185 kDa glycoprotein that contains an extracellular ligand binding domain and intracellular tyrosine kinase activity. HER-2 protein staining is observed only in low levels in epithelial cells of most organs in normal human tissues and at slightly higher levels in fetal tissues. HER-2 protein is useful in identifying cancer cells with increased aggressiveness. Soluble p97–115 HER-2 (the soluble circulating fragment of p185 HER-2) protein levels in serum can be used as a diagnostic tool for monitoring the extent of tumor spread, postoperative relapse and/or metastatic risk for different cancers.