The plasma metabolomics revealed differential metabolites were mainly involved in cysteine and methionine metabolism, histidine metabolism, pentose, and glucuronate interconversions, alanine, aspartate, glutamate metabolism and other pathways in MDM2 methylated group and MDM2 unmethylated group of HBV-related HCC (Figures 9C,D). The gene discussed is MDM2; the disease is hepatocellular carcinoma.