TGFB1 and pancreatic ductal adenocarcinoma: Exosomes derived from pancreatic ductal adenocarcinoma (PDAC) cells, enriched with MIF, activate Kupffer cells and induce the release of TGF-β. This cytokine, in turn, stimulates hepatic stellate cells to secrete fibronectin, thereby facilitating metastatic progression, as demonstrated through combined human and mouse in vivo studies.