Based on the extent of global DNA methylation, IDH-mut/G-CIMP+ tumors have been further divided into two distinct subgroups characterized by different outcomes: G-CIMP-low gliomas with a low degree of DNA methylation and unfavorable clinical outcome and G-CIMP-high gliomas characterized by higher DNA methylation and better outcome [23,24]. Here, IDH1 is linked to central nervous system cancer.