TP53 and glioblastoma: The activity of SMases in glioblastoma is still being elucidated, but it has been shown that acid SMase may sensitize glioma cells to chemotherapy and radiation by increasing metabolism of sphingomyelin to ceramide and consequent apoptosis in the context of p53-deficiency; conversely, neutral SMase may be involved in increasing ceramide production in p53-wildtype cells (129).