Metabolic theory of cancer: from Warburg to oncometabolites

The claim. Warburg's form (1924, restated in Science in 1956): the origin of cancer is irreversible injury to respiration, followed by a switch to fermentation; everything else, including mutations, is secondary. Seyfried's form (2010): cancer is a mitochondrial metabolic disease, genomic instability is downstream of damaged energy metabolism, and restricting glucose and glutamine while supplying ketones should control it. The modern reading (Vander Heiden, Cantley and Thompson 2009; Pavlova and Thompson 2016): aerobic glycolysis and the other metabolic hallmarks are programmed by oncogenic signalling (PI3K/AKT, MYC, HIF, RAS) to supply carbon, nitrogen and reducing power for building a new cell, and metabolic enzymes can be oncogenes when their mutation produces an oncometabolite.

Who and when. Warburg 1924 and 1956. Seyfried and Shelton, Cancer as a metabolic disease, 2010. Vander Heiden, Cantley and Thompson, Understanding the Warburg effect, 2009. IDH1 mutations in glioma (2008) and the oncometabolite 2-hydroxyglutarate (2009) gave the theory its clearest modern case.

Evidence for. Aerobic glycolysis is near universal and is the basis of FDG PET imaging. Mutations in IDH1 and IDH2, succinate dehydrogenase and fumarate hydratase cause cancers by producing metabolites that block DNA and histone demethylation, so metabolism can be the initiating lesion. Hypoxia and lactate shape the microenvironment and suppress T cells; nutrient competition is a mechanism of immune escape. Obesity and diabetes raise cancer risk.

Evidence against and limits. Most cancer cells have functional mitochondria and depend on them; the Warburg effect is usually downstream of signalling, not of respiratory damage. Nuclear transfer experiments cut both ways. Ketogenic diets have been safe but have shown no anti-tumour benefit in trials (ERGO2 and others), and glycolysis inhibitors such as dichloroacetate and 2-deoxyglucose failed clinically. Seyfried's causal claim does not account for the thousands of tumours whose sequencing shows clear driver mutations with intact respiration.

Predictions that held or failed. Held: tumours take up glucose avidly (PET); metabolic enzymes can be cancer genes; IDH inhibitors treat IDH-mutant leukaemia and glioma. Failed: respiration damage as the universal origin; dietary glucose restriction as a treatment; glutaminase inhibition (telaglenastat) in randomised trials.

Therapies that came from it. FDG PET for staging and response, IDH inhibitors (ivosidenib, vorasidenib), antimetabolites and asparaginase in a broad sense, and the exploration of lipid synthesis, glutamine and one-carbon metabolism as targets. Metabolism became a hallmark in 2011. The atavistic theory treats fermentation as an ancestral programme, and the epigenetic theory absorbs the oncometabolite mechanism.

Status: partly confirmed. Metabolic reprogramming is established as a hallmark and, through oncometabolites, as an occasional cause; the claim that damaged respiration is the origin of cancer is superseded.