Epidermal Growth Factor Receptor 2 Extracellular Domain II (HER2 ECD II)

Epidermal growth factor receptor 2 (HER2, also known as ERBB2 or Neu) is a member of the epidermal growth factor receptor (EGFR/ERBB) family of transmembrane tyrosine kinase receptors. The extracellular domain (ECD) of HER2 is responsible for ligand binding and dimerization, which are critical steps in activating downstream signaling pathways that regulate cell proliferation and survival. Extracellular domain 2 (ECD II) refers specifically to the second subdomain within the ECD, which plays a role in receptor dimerization. Unlike other EGFR family members, HER2 does not have a known direct activating ligand; instead, it acts as a preferred dimerization partner for other ERBB receptors. Overexpression or amplification of HER2 occurs in approximately 15–30% of breast cancers and up to ~30% in gastric/gastroesophageal cancers. Elevated serum levels of soluble HER2 (sHER2/HER2ECD), released into circulation by proteolytic cleavage, correlate with tumor burden and may predict response to anti-HER2 therapies such as trastuzumab.

Other names

ERBB2 ECD IINeu

Inhibits HER2 signaling by blocking downstream signaling and mediating immune responses.