For those with HER2-positive breast cancer, therapies involving drugs that target HER2, including trastuzumab [15, 16], pertuzumab [17], trastuzumab-emtansine [18, 19], and tyrosine kinase inhibitors of HER2, such as neratinib [20], pyrotinib [21], tucatinib [22, 23], and trastuzumab deruxtecan, which were recently approved for HER2-positive breast cancer [24], are currently being applied and can lead to significant improvement in survival. The gene discussed is ERBB2; the disease is breast carcinoma.