IDH1 and central nervous system cancer: Similar cancer cell hierarchies have been described for high-grade pediatric gliomas, as well as for IDH mutant and IDH wildtype adult gliomas (Tirosh et al., 2016; Venteicher et al., 2017; Filbin et al., 2018; Neftel et al., 2019; Couturier et al., 2020).