HER2

Antigen Background

HER2 is a transmembrane receptor tyrosine kinase and a member of the human epidermal growth factor receptor (HER/ErbB) family, encoded by the ERBB2 gene. HER2 is involved in the regulation of cell growth, survival, differentiation, and proliferation through activation of downstream signaling pathways such as PI3K/AKT and MAPK. Aberrant HER2 overexpression or gene amplification leads to constitutive signaling and is a key driver of oncogenesis, tumor aggressiveness, disease progression, particularly in breast cancer. It is reported to be expressed in normal epithelial tissues at low levels, while HER2 overexpression or amplification is observed in a subset of breast cancers and across a wide range of other malignancies, including gastric, gastroesophageal, colorectal, lung, bladder (urothelial), ovarian, endometrial, and prostate cancers, with expression frequency and clinical relevance varying by tumor type.

Disclaimer

HER2 is recommended for the detection of specific antigens of interest in normal and neoplastic tissues, as an adjunct to conventional histopathology using non-immunologic histochemical stains.