To further investigate the relationships among BC-derived exosomal miR-221-3p, LIFR, and the functions of hCMEC/D3 cells, we cotransfected anti-miR-221-3p and shLIFR into hCMEC/D3 cells, and the changes in the protein expression of LIFR in hCMEC/D3 cells were confirmed by WB analysis (Supplementary Figure 1C). Here, LIFR is linked to breast cancer.