Estrogen/Progesterone receptor status, short for ER and PR status, is a test to determine if a breast cancer tumor is positive for estrogen and progesterone receptors.
What does the test result mean?
ER and PR testing of breast tumor tissue determines if one or both types of receptors are present. The results include:
- ER-positive and PR-positive: a better than average prognosis and a more intense response to endocrine therapy.
- ER-negative but PR-positive, or ER-positive but PR-negative: still benefiting from endocrine therapy but may having a decreased response.
- ER-negative and PR-negative: not likely to benefit from endocrine therapy.
An individual’s response to endocrine therapy will depend on a variety of factors, but typical response rates include:
- ER-positive, PR-positive: 75-80%
- ER-positive, PR-negative: 40-50%
- ER-negative, PR-positive: 25-30%
- ER-negative, PR-negative: 10% or less
Keywords: estrogen/progesterone receptor status; ER and PR status