Notch-1-deleted endothelial cells therefore preferentially become tip cells, which promotes an abnormal vasculature.72,73 The anti-malaria drug chloroquine was found to induce vessel normalisation by stimulating the Notch-1/DLL4 signalling pathway.74,75 In vivo, chloroquine reduced the tumour mass and improved the tumour milieu by increasing tissue perfusion, thereby lowering hypoxia and reducing tumour cell invasion while enhancing tissue sensitivity to chemotherapy. This evidence concerns the gene DLL4 and neoplasm.