ER IHC Testing in Accordance with Guidelines Established the American Society of Clinical Oncology (ASCO) and by the College of American Pathologists (CAP).
Therese Phillips, Anna Strickland, Scott Webster, Rosanne Welcher. Dako North America, Inc., Carpinteria, CA
Background: A recent and important event in the field of breast cancer diagnostics is the publication of consensus guidelines for hormone receptor testing jointly formulated by ASCO/CAP1. As noted by the ASCO/CAP panel, the ER/PR pharmDx™ kit (Dako) is one example of an assay format that meets the clinical and analytical criteria against which laboratories can validate their assays. In this study IHC protocols based on the anti-ER monoclonal antibodies 1D5 (mouse) and SP1 (rabbit) were compared to ER pharmDx staining of breast cancer tissue.
Design: Protocols developed for concentrated versions of 1D5 and SP1 were validated against ER pharmDx according to the recommended procedures. Formalin fixed, paraffin embedded breast cancer specimens were chosen for this purpose based on their ER status (determined from prior screening with ER pharmDx):
|ER Status||# Specimens (1D5 Study)||# Specimens (SP1 Study)|
|1% - 10% Positive||6||8|
|> 10% Positive||55||30|
|Metric||1D5 vs. pharmDx||SP1 vs.pharmDx|