In fact, the expression of PEDF affects the glioma TME by downregulating the production of matrix metalloproteinase-9 (MMP9), the vascular endothelial growth factor (VEGF), and the basic fibroblast growth factor (bFGF), leading to the inhibition of cancer cell invasiveness and promoting the apoptosis [14]. This evidence concerns the gene MMP9 and glioma.