The categories are; (1) diffuse astrocytoma MYB (MYB proto-oncogene, transcription factor)- or MYB proto-oncogene-like 1 (MYBL1)-altered, (2) angiocentric glioma (characterised by MYB alterations), (3) polymorphous low-grade neuroepithelial tumour of the young (PLNTY; abnormalities in BRAF (B-Raf, proto-oncogene, serine/threonine kinase) and fibroblast growth factor receptor (FGFR) family), and (4) diffuse low-grade glioma, mitogen-activated protein kinase (MAPK) pathway-altered (FGFR1, BRAF). The gene discussed is BRAF; the disease is diffuse astrocytoma.