EGF Receptor,also known as ERBB, ERBB1 and HER1, is a type I transmembrane protein belonging to the tyrosine protein kinase family. It binds to a subset of EGF family ligands, including EGF, TGF-alpha, amphiregulin, EPGN, BTC, EREG and HBEGF. Ligand binding triggers receptor homo- or hetero-dimerization, which induces downstream kinase activation, tyrosine phosphorylation and cell signaling. EGF receptor signaling has been shown to regulate cell proliferation, differentiation, motility and apoptosis.