Prosigna provides a highly precise method for measuring breast cancer genomic signatures from formalin-fixed paraffin-embedded (FFPE) tissue2.
Objective: Assess 2 aspects of Prosigna’s analytical robustness when used in qualified clinical laboratories: reproducibility when starting from tissue and precision when starting from RNA.
Starting from tissue, total standard deviation was only 2.9 Prosigna Score units across 3 independent sites.
- Reproducibility was assessed by testing a panel of 43 FFPE blocks across 3 sites, including independent H&E review, macrodissection, and RNA isolation by lab personnel at each site.
- Average site-to-site concordance of risk category was >90%, and there were no low-to-high-risk misclassifications or vice versa.
Starting from RNA, total standard deviation was <1 Prosigna Score unit regardless of testing site, operator, and reagent lot.
- Precision was assessed by testing 5 pooled FFPE breast tumor RNA samples >100 times each.
- RNA samples were run independently at 3 different testing sites by a total of 6 different operators using 3 different reagent lots.
- The range of Prosigna Scores for 108 independent measurements was ≤4 units for each of the 5 sample pools.
- 100% concordance was shown between measured and expected risk group results.
1. Prosigna [Package Insert]. Seattle, WA: NanoString Technologies, Inc; 2013.
2. Nielsen T, Wallden B, Schaper C, et al. Analytical validation of the PAM50-based Prosigna Breast Cancer Prognostic Gene Signature Assay and nCounter Analysis System using formalin-fixed paraffin-embedded breast tumor specimens [published online ahead of print March 13, 2014]. BMC Cancer. 2014. doi:10.1186/1471-2407-14-177.
Prosigna is indicated for in vitro diagnostic use in postmenopausal women with hormone receptor-positive, node-negative (Stage I or II), or node-positive (Stage II) breast cancer to be treated with adjuvant endocrine therapy for assessment of risk of distant recurrence of disease.