VTN and cancer: The PDAC stroma is a highly complex structure composed by several extracellular molecules, such as collagen (mainly type I), vitronectin, fibronectin, hyaluronic acid, molecular growth factors, and several specialized cells including endothelial cells (blood vessels), neural cells, cancer stem cells, immune cells, pancreatic stellate cells (PSCs), and cancer-associated fibroblasts (CAFs) [74,77].