DLL4 and central nervous system cancer: To clarify whether NOTCH1 is involved in PDGF‐D‐mediated EMT in glioma cells, we activated NOTCH1 in the PDGF‐DKD LN18 cells with Dll4 and inhibited NOTCH1 cleavage in the PDGF‐DOE U87 cells using DAPT.