To further validate the role of the miR-216a-5p/ITCH axis in a more clinically relevant patient-derived xenograft (PDX) model, we established a breast cancer PDX model in female NSG mice using primary tumor tissues (Supplementary Fig. 19a) and administered AAV9 at a different time point (for treatment rather than prevention; 2 weeks after DOX exposure, when cardiac function started to be significantly impaired, as revealed by serial echocardiography) (Supplementary Fig. 19b). The gene discussed is ITCH; the disease is breast carcinoma.