We extrapolated data from a large monoinstitutional series of patients who had undergone surgery for breast cancer to assess the validity and clinical impact, in terms of DDFS, of the modified surrogate updated definitions of the “luminal A” and “luminal B (HER2-negative)” intrinsic molecular subtypes of breast cancer outlined in the 2011 and 2013 versions of the St Gallen International Expert Consensus on the Primary Therapy of Early Breast Cancer guidelines [1,3]. Here, ERBB2 is linked to breast cancer.