EGFR, HER2, ErbB4

The ErbB family consists of four closely related cell-surface receptor tyrosine kinases: EGFR (also known as ErbB1 or HER1), HER2 (ErbB2), HER3 (ErbB3), and ErbB4 (HER4)[1][3][7]. These receptors are activated upon binding of specific ligands, subsequently dimerizing (either as homodimers or heterodimers), and triggering a cascade of intracellular signaling that regulates cell growth, survival, differentiation, and migration[1][5][6][7]. EGFR and ErbB4 are fully functional kinases that bind ligands and autophosphorylate; HER2 has no known ligand and functions predominantly as a preferred dimerization partner, potentiating signaling when overexpressed or heterodimerized with other ErbB receptors[3][6][7]. Dysregulation—through overexpression, gene amplification, mutations, or fusions—is a central driver in many solid tumors, making these proteins important targets for small molecule inhibitors and monoclonal antibodies[1][6][7]. They are also implicated in non-malignant diseases when signaling is either excessive or deficient[3][5][7]. Grouped as "EGFR, HER2, ErbB4," these are not a single molecular entity, but a set of key targets frequently co-targeted in cancer therapy due to their overlapping signaling functions and frequent co-aberrations in tumors[1][3][5].

Other names

ErbB1HER1ErbB2neuHER4

Inhibition of tyrosine kinase activity (small molecule TKIs) Blockade of ligand binding or receptor dimerization (monoclonal antibodies) Induction of receptor internalization and degradation