We found that HEATR5B-881aa reduced JMJD5 protein expression without influencing JMJD5 mRNA expression, and JMJD5 overexpression rescued glycolytic and proliferative inhibition induced by HEATR5B-881aa, indicating that HEATR5B-881aa inhibits glycolysis and proliferation in GBM cells by downregulating JMJD5 at the protein level. This evidence concerns the gene KDM8 and glioblastoma.