|Values are valid only on day of printing.|
The test is most frequently used in breast carcinomas when decisions on hormonal therapy must be made.
While the test can be performed on any formalin-fixed, paraffin-embedded tissue, it is infrequently used for non-breast cancer specimens.
The steroid hormone receptors, estrogen receptor (ER) and progesterone receptor (PR), are commonly used in the management of women with breast cancer. ER and PR status provide an indication of prognosis and of the potential to benefit from hormonal therapy. Generally, ER/PR-positive tumors are more likely to respond to endocrine therapy and have a better prognosis, stage-for-stage, than receptor-negative tumors.
Negative: <1% reactive cells
Focal positive: 1-10% reactive cells
Positive: >10% reactive cells
Immunoperoxidase-stained slides are examined microscopically by the consulting anatomic pathologist and interpreted as negative (<1% reactive cells), focally positive (1%-10% reactive cells), or positive (>10% reactive cells).
The performance and quality of immunohistochemical (IHC) stains for formalin-fixed, paraffin-embedded tissue depends critically on proper fixation of tissue specimens. IHC staining of steroid hormone receptors is especially sensitive to fixation conditions (see Specimen Required for specific handling instructions).
1. Ogawa Y, Moriya T, Kato Y, et al: Immunohistochemical assessment for estrogen receptor and progesterone receptor status in breast cancer: analysis for a cutoff point as the predictor for endocrine therapy. Breast Cancer 2004;11(3):267-275
2. Fisher ER, Anderson S, Dean S, et al: Solving the dilemma of the immunohistochemical and other methods used for scoring estrogen receptor and progesterone receptor in patients with invasive breast carcinoma. Cancer 2005;103(1):164-173