The addition to chemotherapy of trastuzumab, a humanized monoclonal antibody that binds to the extracellular domain of HER2 receptors, significantly improved survival in patients with early-stage HER2-positive BC (2), but despite the improvement in both disease-free survival (DFS) and overall survival (OS) in early HER2-positive BC, long-term follow-up data indicate that approximately 25% of patients still develop disease recurrence (3). Here, ERBB2 is linked to breast cancer.