ERBB2 and breast cancer: According to the frequency of occurrence, the keywords “expression”, “cancer”, “monoclonal antibody”, “open-label”, “chemotherapy”, “breast cancer”, “treatment”, “antitumor activity”, “brentuximab vedotin”, “phase II trial”, “trastuzumab emtansine”, “antibody-drug conjugates”, “ HER2” and other keywords were obtained.