MMP9 and glioblastoma: Similarly, Kucharzewska et al. reported that exosomes from glioblastoma multiforme (GBM) cells cultured under hypoxia were enriched in matrix metalloprotease-9 (MMP-9), pentraxin 3, IL-8, PDGF, and Plasminogen activator inhibitor-1 (PAI-1), reflecting the hypoxic gene expression of donor cells and GBM tumors [132].