IDH1 and pleomorphic xanthoastrocytoma: Further, histone 3 and IDH1/2 wild-type pGBM can be subdivided into three subgroups: (1) receptor tyrosine kinase, characterized by the deletion of CDKN2A/B, the mutation of TP53, and the amplification of EGFR and PDGFRA; (2) mesenchymal, characterized by mutations in NF1; and (3) pleomorphic xanthoastrocytoma (PXA)-like, characterized by the deletion of CKDN2A and BRAF V600E mutations.