CLDN5 and glioblastoma: Importantly, our very recent report found that GBM cancer cell membrane (CCM) camouflaged nanoparticles possess excellent BBB permeability mediated by down regulation of tight-junction proteins including Zonula occludens-1 (ZO-1), Claudin-5 and Occludin thereby decreasing the tightness of endothelial cells30.