IDH1 and central nervous system cancer: Our findings confirm large-scale methylome analyses that identified a subset of IDH-mutant astrocytomas with lower levels of global DNA methylation and shorter survival, which were referred to as “glioma-CpG island methylator phenotype (G-CIMP)-low” tumors as opposed to “G-CIMP-high” tumors [11, 31, 42, 43].