Lewis C. Cantley and colleagues found that tumor M2-PK, a form of the pyruvate kinase enzyme, promotes the Warburg effect. Tumor M2-PK is produced in all rapidly dividing cells and is responsible for enabling cancer cells to consume glucose at an accelerated rate; on forcing the cells to switch to pyruvate kinase's alternative form by inhibiting the production of tumor M2-PK, their growth was curbed. The researchers acknowledged the fact that the exact chemistry of glucose metabolism was likely to vary across different forms of cancer; however, PKM2 was identified in all of the cancer cells they had tested.