Epidermal Growth Factor Receptors, EGFRs

The epidermal growth factor receptor (EGFR) is a transmembrane protein that is a receptor for members of the epidermal growth factor family (EGF family) of extracellular protein ligands. EGFR is activated by binding of its specific ligands, including epidermal growth factor and transforming growth factor alpha (TGF-α). The EGFR is essential for ductal development of the mammary glands, and agonists of the EGFR such as amphiregulin, TGF-α, and heregulin induce both ductal and lobuloalveolar development even in the absence of estrogen and progesterone.