PKM and cancer: Indeed, we found that all the transitions from 2 to 3D cultures, regardless of the cancer cell type and cell culture conditions, are accompanied by the significant up-regulation of genes encoding for 6 out of 10 glycolytic enzymes: HK2 and ALDOC belonging to the energy-requiring phase and GAPDH, PGK1, ENO2, and PKM belonging to the energy-releasing phase [104].