ART4 and neoplasm: Epidermal growth factor receptor (EGFR) is a glycoprotein with tyrosine kinase activity that is a major member of the erythroblastosis oncogene B (ErbB) family.201 The EGFR family contains four subtypes: EGFR (ErbB1, HER1), ErbB2 (HER2), ErbB3 (HER3), and ErbB4 (HER4).202 EGFR is involved in tumor cell proliferation, angiogenesis, tumor invasion, metastasis, and inhibition of apoptosis.