PFKFB3 and cancer: To assess whether F1 focus metabolism is rewired into the Warburg effect, we investigated the expression of PKM2 isoform of pyruvate kinase, which is often expressed in cancer cells, as well as the expression of the PFKFB3 isoform of the bifunctional phosphofructokinase/fructose bisphosphatase (PFK/FBP) enzyme.