By contrast, in case of HA degradable genes, the expression of hyaluronidases (HYALs), which are responsible for HA matrix catabolism, did not differ between normal and GBM samples, except HYAL2. However, in case of MMPs, the representative proteases MMP2 and MMP9 were highly increased in GBM tissue. Here, MMP9 is linked to glioblastoma.