Furthermore, patients with HER2-low breast cancers were more likely to be diagnosed in the early 2010s (p < 0.001) and to receive total mastectomy (37.0% vs. 36.3%, p < 0.001) and hormonal treatment (80.1% vs. 70.9%, p < 0.001) but were less likely to receive neoadjuvant and adjuvant chemotherapy (NAC: 8.7% vs. 10.8%; AC: 23.8% vs. 25.4%, both p < 0.001) (Table 1). Here, ERBB2 is linked to breast cancer.