It has been reported that both in vitro and in vivo, the tumor-enclosing astroglial scar-housed microglia, compared to those in GBM alone, released 3.2-fold more glutamate to stimulate astrocytic monoamine oxidase-B (MAO-B) activity and chondroitin sulfate proteoglycans (CSPGs) deposition to restrict GBM growth [41]. This evidence concerns the gene MAOB and neoplasm.