Estrogen Receptor Status

**Semantic type:** Laboratory or Test Result

**Definition:** The estrogen receptor level measured in a primary tumor or in metastases. There are essentially two distinct forms of breast cancer, one that tends to have an early onset and is characterized by an ER- status, and one that tends to have a late onset and is characterized by an ER+ status. However, these two variants tend to overlap with respect to age, so it is possible for a young woman to have a "late-onset" form of breast cancer and for an older woman to have an "early-onset" variant of the disease.

**Synonyms:** - ER Alpha Status - ER Status - ER-Alpha Status - ERA Status - ESR Status - ESR1 Status - ESRA Status - ESTRR Status - Estrogen Receptor - Estrogen Receptor 1 Status - Estrogen Receptor Alpha Status - NR3A1 Status - Nuclear Receptor Subfamily 3 Group A Member 1 Status