MTOR and central nervous system cancer: Again, several reports have found that mTOR pathway is frequently activated in other low-grade astrocytomas such as pediatric low-grade glioma (PLGG) and pilocytic astrocytoma (PA) [134, 135], while to date there are only few morphological studies regarding the role of mTOR in anaplastic astrocytoma (WHO grade III glioma) [136–138].