label: Estrogen Receptor Status
label_lc: estrogen receptor status
description: "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."