As an example, the last update of WHO classification (5th edition) incorporated (i) CDKN2A/B homozygous deletion in IDH-mutant astrocytomas (covering grades 2–4), (ii) TERT promoter mutation, EGFR amplification, and + 7/− 10 copy number changes in IDH-wildtype diffuse astrocytomas as well as (iii) MYB- or MYBL1 mutations in diffuse astrocytoma. The gene discussed is CDKN2A; the disease is diffuse astrocytoma.