MGMT promoter is methylated in 85 and 98% of IDH mutant astrocytomas and oligodendrogliomas, respectively, (Turcan et al., 2012; Capper et al., 2018; Mollemann et al., 2005; Mulholland et al., 2012; Horbinski et al., 2021) and this phenotype is part of the G-CIMP signature (Noushmehr et al., 2010; van den Bent et al., 2011; Laffaire et al., 2011). The gene discussed is IDH1; the disease is astrocytoma (excluding glioblastoma).