In a pan-glioma unsupervised cluster analysis, Ceccarelli et al. (2016) previously identified specific methylation subtypes LGm1/LGm2/LGm3, which carried IDH1 or IDH2 mutations, were enriched for lower-grade gliomas, and presented with a genome-wide hypermethylation compared to other methylation clusters. Here, IDH1 is linked to central nervous system cancer.