ERBB2 and breast carcinoma: A limited number of patients can receive standard second-line therapy (DS-8201 or T-DM1) for metastatic HER2-positive in some parts of the world, including China, due to many factors, such as cost-benefit ratios.<h4>Case</h4>A 51-year-old premenopausal woman was diagnosed with HER2-positive breast cancer.