The NSABP B-31 trial testing the efficacy of adjuvant trastuzumab was almost derailed right after launching because 18% of the enrolled patients were found to be ERBB2-negative (formerly HER2 or HER2/neu) on central review of the initial 104 patients.1 This prompted international efforts to improve reliability of ERBB2 testing, eventually leading to American Society of Clinical Oncology/College of American Pathologists Guideline for HER2 Testing. Ironically, OncotypeDx owes its creation to this event.
Kim JY, Kim S, Paik S. Prognostic Tests for Estrogen Receptor–Positive Breast CancerNeed for Global Consideration and Further Evolution. JAMA Oncol. 2016;2(2):180–182. doi:10.1001/jamaoncol.2015.4343