AKT1 and central nervous system cancer: Higher levels of AKT, mTOR, and S6K phosphorylation in high-grade glioma compared with low-grade glioma have been also reported by Li et al., who analyzed 87 tissue samples and found that the percentage of patients with high AKT, mTOR, and S6K phosphorylation, as detected by immunohistochemistry, was greater in grades III and IV than in grades I and II glioma [49] (Table 1).