TP53 and glioblastoma: MDM2 negatively regulates p53 via various mechanisms such as cell cycle control, genome stability, apoptosis, and tumor neoangiogenesis by ubiquitination, transcription factor activation, and regulation of mRNA stability [40].MDM2 is overexpressed in various human tumors, including sarcoma, leukemia, breast carcinoma, melanoma, and glioblastoma [41].