TP53 and central nervous system cancer: However, loss of tumor suppressors such as p53 or oncogenic activity which converges on PI3K (phosphatidylinositol 3-kinase) can augment mTOR activity, resulting in glioma development (Cancer Genome Atlas Research Network, 2008; Akhavan et al., 2010; Levine and Puzio-Kuter, 2010; Duzgun et al., 2016).