Identifies estrogen receptor, a receptor that belongs to a superfamily of nuclear hormone receptors and is expressed in about 85% of invasive breast cancers. It is a weak prognostic factor but strong predictive factor for response to endocrine therapies, both in adjuvant and metastatic settings. The primary use of assessing ER in breast cancer is to predict response to hormonal therapies such as tamoxifen, other selective estrogen receptor modulators, and aromatase inhibitors. In univariate analysis, moderate to strong staining in even 1% of invasive tumor cells is associated with significant improvement in disease-free survival compared to those patients without ER expression in a tumor.
A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen typeorOne (1) unbaked, unstained slide for H&E staining (required) and two to three (2-3) positively charged unstained slides (all cut at 4-5 microns) for each test/antibody orderedBlock and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.