EGFR (Epidermal growth factor receptor) is a transmembrane protein kinase that serves as a receptor for epidermal growth factor. Binding of the protein to its ligand induces receptor dimerization, tyrosine autophosphorylation, and activation of signal transduction pathways involved in regulating cell proliferation, differentiation, and cell survival. EGFR is overexpressed in a variety of cancers and correlated with a poor prognosis. Gene amplification of EGFR is a frequent occurrence in some types of breast and other cancers, such as carcinomas of the lung, pancreas, head and neck, and glioblastoma. In breast cancer, roughly half of triple negative and also IBC (inflammatory breast cancer) cases show overexpression of this protein. Expression is generally associated with the basal subtype but is also seen in some luminal B tumors, and is correlated with lower ER/PR expression. Expression of EGFR is cytoplasmic and membranous. References: Masuda, 2012; Changavi, 2015; Int J Rad Onc Bio Phys 2004 59(Sup):21; Cancers (Basel) 2017 9(5):52