ERBB2 and squamous cell carcinoma: The Epidermal Growth Factor Receptor (EGFR) is overexpressed in up to 90% of all squamous cell carcinomas of the head and neck (SCCHN)1, and EGFR overexpression is linked with poor prognosis.2,3 The EGFR is a member of the HER tyrosine kinase receptor family composed of four different receptors (EGFR/c-erbB-1, c-erbB-2/HER-2/neu, c-erbB-3/HER-3, and c-erbB4/HER-4), all of which are transmembrane proteins with tyrosine kinase activity.4 The EGFR has an extracellular domain which provides a ligand-binding site.