However, given that these NF1-associated high-grade gliomas occur almost exclusively in adults and not during childhood, we speculate that a subset of these tumors evolve from transformation of a lower-grade precursor over time, perhaps specifically those with piloid features and a DNA methylation signature aligning with HGAP given the overlapping histologic features with pilocytic astrocytoma? This evidence concerns the gene NF1 and pilocytic astrocytoma.