Clinical validation of the Prosigna breast cancer prognostic gene signature assay on formalin-fixed paraffin embedded breast cancer tumors with comparison to standard molecular markers.

e11518 Background: The Prosigna Breast Cancer Prognostic Gene SignatureAssay is a FDA-cleared test for assessing the risk of cancer recurrence in women with hormone receptor positive breast cancer. The assay is based on the PAM50 gene signature, which generates a numeric risk score (0-100) and a risk category. The studies described here were used to validate the FDA-cleared test for routine use in the clinical laboratory. Methods: Thirty-two FFPE breast tumors with known node status, tumor size and ER/PR/HER2 status by IHC were categorizedfor risk of recurrence by a molecular pathologist. Outcome data was available for an additional 10 of the breast tumor samples. RNA was extracted from all 42 tumor samples and analyzed on the Prosigna assay. Results of the Prosigna assay - which produces both a risk score and categorization– were compared to the previously determined risk categorizations. To measure reproducibility of the Prosigna scores, two tumor samples were extracted three times each and analyzed ...