Epidermal growth factor receptor (EGFR), Receptor tyrosine-protein kinase erbB-2 (HER2), and Receptor tyrosine-protein kinase erbB-4 (HER4) (EGFR/HER2/HER4)

The Epidermal Growth Factor Receptor (EGFR) family, specifically HER1 (EGFR), HER2 (ErbB2), and HER4 (ErbB4), consists of transmembrane receptor tyrosine kinases that play critical roles in regulating cell growth, survival, and differentiation (UniProt P00533, P04626, Q15303). These receptors share a conserved intracellular tyrosine kinase domain that, upon ligand binding or dimerization, phosphorylates downstream signaling proteins to activate pathways such as MAPK/ERK and PI3K/Akt (StatPearls, 2023). Dysregulation of these receptors, through gene amplification or activating mutations, is a primary driver in various malignancies, including non-small cell lung cancer and breast cancer (PubMed, PMID: 29401658). Therapeutic agents targeting these kinase domains include small-molecule inhibitors that compete with ATP, thereby preventing the autophosphorylation necessary for signal propagation (PubChem, CID: 11511120). Drugs like afatinib and neratinib are designed as pan-HER inhibitors to irreversibly bind to these domains, providing a more comprehensive blockade than single-target agents (FDA Label: Gilotrif, 2013). While targeting these receptors is effective for tumor suppression, it can also lead to adverse effects in healthy tissues where these receptors maintain epithelial homeostasis (NIH, 2022). Clinical monitoring often focuses on managing gastrointestinal and dermatological toxicities, which are common side effects of inhibiting this receptor family (Journal of Clinical Oncology, 2018). Biomarkers such as HER2 amplification or specific EGFR mutations are critical for identifying patients most likely to benefit from these targeted therapies (Nature Reviews Cancer, 2020).

Other names

ErbB familyHER familyErbB1/ErbB2/ErbB4Human epidermal growth factor receptor familyPan-HER

Inhibition of the intracellular tyrosine kinase domains by competing with ATP for binding, thereby preventing autophosphorylation and downstream signaling through the MAPK, PI3K/Akt, and STAT pathways (StatPearls, 2023; PubChem, 2024).