ERBB2 and breast cancer: Most of the previous retrospective studies that received neoadjuvant chemotherapy or postoperative traditional therapy have shown different clinical characteristics and clinical outcomes of HER2-low breast cancer.35–38 We compared HER2-low and HER2-0 MBC patients receiving chemotherapy, and found no difference in PFS or OS between HER2-low and HER2-0 MBC patients.