PLAU and central nervous system cancer: The TGF-β isoform TGF-β2 induces degradative enzymes matrix metalloproteases (MMP2 and MMP9) that upon activation by membrane type 1-matrix metalloproteinase (MT1-MMP) and urokinase plasminogen activator (uPA) degrade the extracellular matrix to promote glioma invasion [22].