MMP2 and glioblastoma: Since radiation is standard treatment for patients with GBM and because radiation-induced changes in invasive phenotype of glioma have been shown to be possibly due to changes in MMP activation, in the present study, we have tested the ability of a plasmid vector-mediated MMP-2 siRNA to modulate the ionizing radiation-induced invasive phenotype in human glioma cell lines, U-251 and U-87.