MMP9 and glioblastoma: In addition, higher HA content is reported to decrease proliferation (U87MG) [45] and increase the expression of genes associated with GBM progression, including HA synthases (patient-derived, GSC11) [172], hyaluronidases (patient-derived, GSC11) [172], MMP-9 (U87MG) [44,45], MMP-2 (U87MG) [45], VEGF (U87MG) [44,45] and HIF-1 (U87MG) [44,45].