In line with the poorer survival, IDH1R132H mutated tumours also had a significantly higher proportion assigned to the prognostically poorer subclass A_IDH_HG (“IDH-mutant, high-grade astrocytoma”, n = 100/366 vs. 9/71, p = 0.036, Chi-squared test) using the subclasses as defined by Capper et al. (“CNS-classifier”) [7]. This evidence concerns the gene IDH2 and astrocytoma (excluding glioblastoma).