Grade II: 1 pilomyxoid pilocytic astrocytoma; 1 pleomorphic xanthoastrocytoma; 3 IDH wild-type grade II diffuse astrocytomas; 3 grade II IDH mutant 1p19q codeleted oligodendrogliomas; 7 grade II IDH mutant 1p19q intact diffuse astrocytomas;. Here, IDH1 is linked to pilocytic astrocytoma.