IDH1 and astrocytoma (excluding glioblastoma): Regarding IDH-mutated grade 4 astrocytomas, the promoter areas of several glycolytic enzyme genes, such as GLAM, enolase 1 (ENO1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), hexokinase 3 (HK3), and lactate dehydrogenase A (LDHA), are hypermethylated [35], leading to decreased gene expression and enzyme production.