Although the sample sizes of these datasets were relatively small in all tumour types (1p/19q codeleted gliomas n = 135 vs. 14; acute myeloid leukemias n = 4 vs. n = 24; chondrosarcomas n = 3 vs. n = 17 for IDH1R132H and non-R132H IDH1/2-mutated tumours respectively), there was less DNA methylation in IDH1R132H vs. non-R132H IDH1/2-mutation tumours (Fig. 5a–c). This evidence concerns the gene IDH1 and glioma.