ERBB2 and breast cancer: Currently, one year of trastuzumab is still the backbone of the adjuvant systemic treatment of all patients with invasive HER2+ early breast cancers.3,5 Pertuzumab has also been approved in the early setting as neoadjuvant or adjuvant treatment for patients with early-stage BC with high risk of recurrence (tumor > 2 cm or lymph node involvement) based on the NeoSphere and the Aphinity trials.6,7 More recently, trastuzumab emtansine (T-DM1) was approved in the adjuvant setting for patients with residual disease post standard trastuzumab-containing neoadjuvant treatments.