GSCs were observed to exhibit an upregulation of O6-methylguanine-DNA methyltransferase (MGMT) [27,28,29], a pivotal factor responsible for mending the primary cytotoxic damage caused by temozolomide [30,31,32,33], a commonly used chemotherapy drug in the treatment of GBM [2,3,4]. This evidence concerns the gene MGMT and glioblastoma.