In the training cohort, patients with HER2-low cancers showed significant differences from those with HER2-positive cancers in age, BI-RADS category, hormone receptor (HR) status, Ki-67 index, clinical T stage, and ultrasound features including AUS report, external and internal CDFI, lesion margin, and posterior echo (all p < .05). The gene discussed is MKI67; the disease is cancer.