MMP9 and central nervous system cancer: Immunohistochemical staining also demonstrated that MMP9 and SPHK1 levels were apparently reduced, but LASS2 and TIMP2 levels were increased in glioma xenografts derived from U-87 MG-pLV-LASS2 cells compared with those derived from U-87 MG-pLV cells (Fig. 5E).