MGMT and glioblastoma: MDM2 suppresses p53 and contributes to drug resistance in glioblastomas, pancreatic, breast, and gastric cancers by regulating factors such as O-6-methylguanine-DNA methyltransferase (MGMT), Musashi-2, and homeobox A13 (HOXA13) (Han et al., 2018; Sato et al., 2011; Sheng et al., 2017).