The study was also performed before the new WHO 2021 classification of nervous system tumors was introduced, which mandates further genetic testing (including homozygous CDKN2A/B deletion for IDH-mutant astrocytomas and TERT promoter mutation, EGFR amplification, concomitant gain of chromosome 7 and loss of chromosome 10 (or just 10q) for IDH-wildtype astrocytomas). This evidence concerns the gene CDKN2A and astrocytoma (excluding glioblastoma).