Biomarker and multigene assay testing in ER positive, HER-2 negative breast carcinomas: An international guidelines-based approach

Abstract As breast cancer treatment options continue to evolve, biomarker and multigene assay testing are now considered a standard part of the clinical evaluation of estrogen receptor (ER) positive, human epidermal growth factor receptor 2 (HER-2) negative breast carcinomas. These methodologies are used to measure recurrence risk and to tailor both hormonal and chemotherapy treatment options. There are several international guidelines which address the use of biomarker and multigene assay testing for ER positive, HER-2 negative breast carcinoma. Each guideline has specific recommendations as to the prognostic and predictive value of the various biomarker and multigene assay methodologies, their clinical utility, and in some cases their cost effectiveness. In this review, we review the guideline recommendations from eight commonly referenced international organizations (American Joint Committee on Cancer, American Society of Clinical Oncology, Associazione Italiana di Oncologia Medica/ Italian Association of Medical Oncology, European Group on Tumor Markers, European Society for Medical Oncology, National Comprehensive Cancer Network, National Institute for Health and Care Excellence, and the St Gallen International Consensus Guidelines) on biomarker and multigene assay testing in ER positive, HER-2 negative breast carcinomas, with a focus on the four most relevant breast cancer biomarkers (ER, progesterone receptor (PR), HER-2, and Ki-67), the five most commonly discussed multigene assays (Oncotype DX®, MammaPrint®, Prosigna®, EndoPredict®, and Breast Cancer IndexTM), with a brief discussion on the emerging BluePrint® multigene assay.