IDH1 and acute lymphoblastic leukemia: We screened RNA-Seq data of all remaining ‘unassigned’ samples of our cohort (n = 22) for the described gene expression signature or IDH1/2 mutations and identified one patient harboring IDH2 p.R140Q, which was confirmed by PCR on gDNA level, contributing to the heterogeneous frequency distribution of molecular subtypes in different BCP-ALL cohorts.