EGF Receptor, also known as ERBB, ERBB1 and HER1, is a type I transmembrane protein belonging to the tyrosine protein kinase family. It belongs to a family of tyrosine kinase receptors including Human EGF Receptors (HER) 2, 3, and 4 which all play important roles in cell growth and differentiation. Their primary ligands are EGF, Heparin-Binding EGF and Transforming Growth Factor α. Upon ligand binding, EGFR undergoes asymmetric dimerization, composed of an “activator” and a “receiver”. EGFR and its family members are disregulated in numerous cancers. In particular, EGFR is overexpressed in many epithelial solid tumors. Evidence suggests EGFR is an excellent target for pharmacologic intervention in Non Small Cell Lung Cancer (NSCLC) due to its high level of expression and prominent role in tumor growth and metastasis.

> 95% as determined by SDS-PAGE