The Prosigna™ Breast Cancer Prognostic Gene Signature Assay (Nanostring® Technologies, Inc., Seattle, WA) is a next-generation test that supplements conventional diagnostic tools, providing relevant information to assist in assessing a breast cancer patient’s risk of recurrence. The test is based on the reported 50-gene classifier algorithm originally named PAM50 and is performed on the nCounter® Dx Analysis System using RNA extracted from formalin-fixed, paraffin- embedded (FFPE) breast tumor tissue samples. Based on the patient expression profiles, the Prosigna assay assigns breast cancer to one of four molecular classes, or intrinsic subtypes: Luminal A, Luminal B, HER2-Enriched (HER2-E), or Basal-like.
Expression data weighted together with clinical variables generates a Risk of Recurrence (ROR) score on a 0-100 scale, which is correlated with the probability of distant recurrence at ten years for post-menopausal women with hormone receptor-positive early stage breast cancer node negative and 1-3 positive lymph nodes. This score classifies patients into three distinct risk groups: low, intermediate, or high. The test is used as a prognostic indicator when there is a clinical need to identify if a patient has a risk of recurrence breast cancer low enough she may receive adjuvant endocrine therapy alone and be spared adjuvant chemotherapy.