IDH2 and astrocytoma (excluding glioblastoma): Prior studies have shown that homozygous deletion of CDKN2A/B is associated with poor survival in IDH-mutant astrocytoma.28–30 Similar to the EOR data here, mOS for all patients who had a homozygous deletion of CDKN2A/B was shorter than that in patients with wildtype CDKN2A/B, but the difference was not statistically significant.