Progesterone Receptor (PR) belongs to a superfamily of nuclear hormone receptors. Estrogen Receptor (ER) induces PR expression, therefore, PR status serves as an indicator of an intact ER pathway. There are two known isoforms of PR; PRα and PRß. The current assays in clinical breast cancer measure both isoforms. PR is expressed in about 60-70% of invasive breast cancers. It is a weak prognostic factor by itself but a modest predictive factor that adds to the predictive value of ER for response to endocrine therapies, both in adjuvant and metastatic settings. The primary indication to assess PR in breast cancer is to predict response to hormonal therapies, such as tamoxifen, other selective estrogen receptor modulators (SERMs) and aromatase inhibitors.
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.
Use cold pack for transport. Make sure cold pack is not in direct contact with specimen.
Global: 48 hours, Image Analysis (tech-only): 36 hours, Tech-Only (stain only): 24 hours