Despite these advances, HER2-positive metastatic BC remains an almost invariably fatal disease, and the efficacy of a single HER2-targeted therapy is transient, particularly for patients who relapse after neoadjuvant therapy containing monoclonal antibody, with median PFS of approximately 1 year and less than 1 year in the first and second lines, respectively13. The gene discussed is ERBB2; the disease is breast cancer.