PKM and glioblastoma: Song et al. reported that circHEATR5B encodes a new protein known as HEAT5bB-881aa, which directly interacts with JMJD5 and destabilizes it by phosphorylating S361, increasing pyruvate kinase M2 (PKM2) enzymatic activity in GBM cells, and inhibiting glycolysis and proliferation to inhibit GBM growth [20].