Epidermal Growth Factor Receptor (EGFR) 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. Recombinant human Epidermal Growth Factor Receptor (rhEGFR) with C-terminal 6xHis-tag produced in Sf9 insect cells is a single glycosylated polypeptide chain containing 627 amino acids. rhEGFR has a molecular mass of 80kDa analyzed by reducing SDS-PAGE and is obtained by proprietary chromatographic techniques at GenScript.