Along this line, array-based DNA methylome profiling using the Heidelberg methylation classifier version v.12.5 identifies two distinct DNA methylation classes of IDH-mutant astrocytoma, namely “astrocytoma, IDH-mutant, lower grade” and “astrocytoma, IDH-mutant, high-grade” (www.molecularneuropathology.org) [9], which largely overlap with the “G-CIMP-high” and “G-CIMPlow” groups, respectively [42]. Here, IDH2 is linked to astrocytoma (excluding glioblastoma).