Taken together, our data suggest that CD24 may be a promising therapeutic target for subtypes of breast cancer with worse prognoses such as the HER2 or TNBC subtype, and CD24-targeted therapy can potentiate the anti-cancer effects of chemotherapy or HER2-targeted therapy and may be effective in the treatment of HER2 therapy-resistant breast cancer or chemotherapy-resistant TNBC. This evidence concerns the gene ERBB2 and breast cancer.