HER2
Pronunciation: HER-two
Also written as: HER2 — Human Epidermal growth factor Receptor 2
Human epidermal growth factor receptor 2; a protein that promotes cell growth and is overexpressed in some breast cancers.
Full Definition
HER2 is a membrane-bound receptor tyrosine kinase that regulates cell growth and division. Approximately 15-20% of breast cancers overexpress HER2 protein or have HER2 gene amplification, which historically indicated a more aggressive tumor with poor prognosis. However, the development of HER2-targeted therapies such as trastuzumab, pertuzumab, and T-DM1 has dramatically improved outcomes for HER2-positive patients. HER2 status is determined by immunohistochemistry and/or in situ hybridization testing and is essential for treatment planning.
Usage
Usage note: Use 'HER2-positive' or 'HER2-negative' as hyphenated compounds when used as adjectives.
In Context
- "The tumor was HER2-positive by immunohistochemistry with a score of 3+." — Pathology report
- "HER2-targeted therapy with trastuzumab was initiated following surgery." — Treatment plan