EGFR

The epidermal growth factor receptor (EGFR) is a 170 kDa transmembrane protein consisting of an extracellular EGF-binding domain, a short transmembrane region and an intracellular domain with ligand-activated tyrosine kinase activity. EGFR is expressed in many normal epithelial tissues, particularly in the basal layers of stratified epithelium and in squamous epithelium. Over expression of EGFR has been observed in many types of neoplasia, as a result of gene amplification and/or increased protein transcription.