The four classes that currently exist include: (1) Diffuse Midline Gliomas, H3 K27-altered; (2) Diffuse Hemispheric Glioma, H3 G34-mutant; (3) Diffuse pediatric-type high-grade glioma, H3-wildtype; and (4) IDH-wildtype, as well as infant-type hemispheric glioma [7,8]. Here, IDH1 is linked to glioma.