Cancer cells maintain their life-style of extremely rapid growth and proliferation thanks to an enzyme called PK-M2 (pyruvate kinase M2) that alters the cells’ ability to metabolize glucose — a phenomenon known as the Warburg effect. Scientists, who seek to reverse this effect and force cancer cells to regain the metabolism of normal cells, have discovered details of molecular events that cause cancer cells to produce PK-M2 instead of its harmless counterpart PK-M1.