MMP9 and anaplastic meningioma: Expression of collagen type V is increased in atypical and anaplastic meningiomas WHO 2/330 and proteomics indicated disturbed collagen biosynthesis and degradation as well as extracellular matrix remodeling in nonskull base meningiomas (WHO 1 and 2).31 Moreover, brain invasive meningiomas might strongly express MMP-9 altering extracellular protein.32 Interestingly, the change in protein-related band intensity is different in comparison to other types of primary or secondary brain tumors.