This analysis shows for the first time 2 main clinical implications of tumor intrinsic subtype differences within ERBB2/HER2-positive EBC, demonstrating that the association of EFS with pCR after chemotherapy plus ERBB2/HER2 targeting is seen only in patients with ERBB2-enriched and basal-like tumors and only ERBB2-enriched patients benefit from dual neoadjuvant ERBB2/HER2-blockade with trastuzumab and lapatinib. Here, ERBB2 is linked to neoplasm.