Explain the Warburg effect and its implications for cancer metabolism.

The Warburg effect describes cancer cells' preference for aerobic glycolysis - fermenting glucose to lactate even with oxygen available - rather than oxidative phosphorylation. This seemingly inefficient metabolism serves multiple purposes: rapid ATP production despite lower yield per glucose, biosynthetic precursor generation (nucleotides, lipids, amino acids from glycolytic intermediates), maintenance of NAD+ for glycolysis continuation, adaptation to hypoxic tumor microenvironments, and generation of acidic environment promoting invasion. Molecular drivers include HIF-1 activation, oncogene effects (Myc, Ras), tumor suppressor loss (p53), and mitochondrial dysfunction. Therapeutic implications: targeting glycolytic enzymes (hexokinase, LDH), exploiting metabolic vulnerabilities, and PET imaging (18F-FDG) for diagnosis. Cancer metabolism is heterogeneous, with some tumors utilizing oxidative metabolism.