Delta like ligand 4 induces impaired chemo-drug delivery and enhanced chemoresistance in pancreatic cancer

► DLL4 positive immunoreactivity was observed in most cases of duct cells from tumor tissues. ► Chemo-drug distribution was broadly consistent with intratumoral blood perfusion. ► Defective angiogenesis caused by DLL4/Notch pathway induced the inefficient drug delivery. ► DLL4 enhanced chemoresistance through the angiogenesis dependent and independent mechanisms.