MMP9 and glioblastoma: Awasthi et al. investigated whether an association may exist in glioblastoma (GBM) between DCE-MRI parameters and tissue matrix metalloproteinase 9 (MMP-9) expression, with MMPs known to be responsible for targeting the extracellular matrix and contributing to BBB permeability and angiogenesis/neovascularization of glial tumors.