MMP2 and central nervous system cancer: A gene delivery system based on the cleavage of PEG-lipid micelles within the MMP2-rich tumour microenvironment was recently used to effectively deliver the DNA repair inhibitor DNA strand break bait (Dbait) into glioma by targeting the low-density lipoprotein receptor-related protein 1 (LPR1), which is implicated in BBB permeability while also being highly expressed in glioma [20].