LEP and breast carcinoma: Notably, leptin modulation of PKM2, an enzyme that converts phosphoenolpyruvate to pyruvate (the final product of glycolysis) in breast cancer cells, cholangiocarcinoma, and breast adipose stromal cells, has been found to be essential for stimulation of the epithelial-mesenchymal transition (EMT), cell migration, and invasion by this adipokine [52,53,54].