PRC1 and breast cancer: Similarly, Jia et al.228showed that miR-139–5p-loaded exosomes from human umbilical cord mesenchymal stem cells (hUCMSCs) downregulated PRC1, inhibited BC progression in vitro and in vivo. Cai et al.229also found that exosomal miR-133b, which is downregulated in BC tissues, inhibited cell proliferation and promoted apoptosis by targeting DUSP1.