Whereas MMP9 overexpression associated with glioma malignancy is accompanied by TIMP-1 overexpression61, the expression status of TIMP-1 and TIMP-2 determined during glioma progression have been highly controversial, suggesting that balance between the expression and/or activity of MMPs and their specific inhibitory proteins may decide glioma progression, including the processes of migration and invasion. This evidence concerns the gene MMP9 and central nervous system cancer.