Estrogen Receptor (ER) belongs to a superfamily of nuclear hormone receptors and is expressed in about 85% of invasive breast cancers. There are two known isoforms of estrogen receptor, ERα and ERß. It is a weak prognostic factor but a strong predictive factor for response to endocrine therapies, both in adjuvant and metastatic settings. The primary indication to assess ER in breast cancer is to predict response to hormonal therapies such as tamoxifen, other selective estrogen receptor modulators (SERMs) and aromatase inhibitors. In univariate analysis, moderate to strong staining in even 1% of the invasive tumor cells is associated with significant improvement in disease-free survival compared to those patients whose tumor lacks ER expression.
- A formalin-fixed, paraffin-embedded (FFPE) tissue block is preferred specimen type
- One (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 ordered
- Block and slide identifiers should be clearly written and match exactly with the specimen ID and specimen labeling as noted on the requisition.
Storage and Transportation
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.
88342 x 1 or 88341 x 1; 88361 x 1; 88360 x 1
Global: 48 hours, Image Analysis (tech-only): 36 hours, Tech-Only (stain only): 24 hours