PFKFB3 and neoplasm: Fructose-2,6-bisphosphate, the catalytic product of PFK2, is an allosteric activator of PFK1, and tumor cells indirectly control the activity of PFK1 by upregulating PFK2 expression, which in turn promotes glycolysis (Yalcin et al., 2009; Bartrons et al., 2018).