Dysregulated transmethylation leading to hepatocellular carcinoma compromises redox homeostasis and glucose formation.

•Loss of glycine N-methyltransferase results in hepatocellular carcinoma.•Metabolic reprogramming ensues to attenuate the increased S-adenosylmethionine.•The metabolic changes include dysregulated liver NAD+ homeostasis and redox state.•Liver glucose formation is reduced and precursors directed to biosynthetic pathways.