The phase 3 HERceptin Adjuvant [HERA; Breast International Group (BIG) 01-01], National Surgical Adjuvant Breast and Bowel Project (NSABP)-B31/N9831, and Breast Cancer International Research Group (BCIRG)-006 studies demonstrated the clinical benefits of 1 year of H IV as adjuvant therapy for the treatment of patients with HER2-positive early breast cancer (EBC) [1–3]. This evidence concerns the gene ERBB2 and breast cancer.