FN1 and pancreatic ductal adenocarcinoma: Recently, Costa-Silva and colleagues demonstrate that MIF-containing exosomes from pancreatic ductal adenocarcinoma (PDAC) cells induce TGF-β production in liver Kupffer cells, which in turn upregulates fibronectin (FN) expression by hepatic stellate cells and enhances recruitment of bone marrow-derived cells, finally leading to the formation of liver pre-metastatic niche [47], suggesting a complicated network that involves cancer cells, stromal cells, and immune cells in exosome-initiated pre-metastatic niche formation.