PTEN and astrocytoma (excluding glioblastoma): Parada et al. induced resultant malignant astrocytoma via early inactivation of Tp53 and Nf1 in mice [30], and demonstrated that manipulation of tumor suppressors (Nf1, Tp53, and Pten) in NSCs and NPCs in vivo is both necessary and sufficient for the formation of astrocytomas (Fig. 1).