CD274 and brain neoplasm: Similarly, the silencing of PD-L1 expression in tumor cells via treatment with human neural progenitor cell-derived EVs modified with PD-L1 siRNA and with a brain-tumor-targeting cyclic RGDyK peptide increases tumor-infiltrating EVs, decreases PD-L1 expression by glioblastoma cells and increases infiltration by Tc cells, showing a synergic effect with radiotherapy [163].