Further studies showed that IDH-mutant G-CIMP-positive tumors with 1p/19q codel status were associated with better overall survival than IDH-mutant G-CIMP-positive tumors with 1p/19q non-codel status (285, 286), and G-CIMP-low non-codel subgroup, based on the extent of DNA methylation, had poorer outcome compared with G-CIMP-high non-codel subgroup in IDH-mutant gliomas (287–290). Here, IDH1 is linked to central nervous system cancer.