MMP9 and central nervous system cancer: These data indicate that PLP2 knockdown could down-regulate matrix metalloproteinase 9 (MMP9) in LN229 and GBM8401 glioma cell lines, and matrix metalloproteinase 2 (MMP2) expression in GBM8401 glioma cell line (* p < 0.05; ** p < 0.01; *** p < 0.001, Figure 8).