PKM and cancer: This is interesting, because it has been proposed that low-activity PKM2 (dimer) leads to the accumulation of building blocks (metabolic intermediates) that meet the requirements of the fast-proliferating cancer cells, whereas high-activity PKM2 (tetramer) favors bioenergetic production that may be essential for the survival of cancer cells under stress conditions, such as nutrient (glucose) starvation [12, 19–21].