ERBB2 and breast cancer: The European Commission Initiative on Breast Cancer (ECIBC) aims to provide evidence-based recommendations for screening and diagnosis of breast cancer.11 The Guidelines Development Group (GDG) of the ECIBC prioritised a clinical question on the use of multigene tests to guide the use of adjuvant chemotherapy in HoR-positive, HER2-negative and lymph node-negative or up to 3 lymph nodes-positive invasive breast cancer.