estrogen receptor negative
Breast cancer cells lacking estrogen receptor expression, affecting hormonal therapy eligibility.
Full Definition
Estrogen receptor negative (ER-negative) describes breast cancer tumors that do not express estrogen receptors as determined by immunohistochemistry testing. Tumors are considered ER-negative when fewer than 1% of cancer cells show nuclear staining for estrogen receptor protein. This classification excludes the use of endocrine therapies such as tamoxifen or aromatase inhibitors, as these treatments target estrogen signaling pathways. ER-negative status is associated with different prognosis and treatment responses compared to ER-positive tumors.
Usage
Usage note: Hyphenate when used as compound adjective; may be abbreviated as ER- in clinical settings.
In Context
- "Estrogen receptor negative status eliminated endocrine therapy options." — oncology consultation
- "The tumor was estrogen receptor negative with strong HER2 expression." — molecular pathology report