(2019), total of 34 known plasma metabolites were detected, and five of them—octanoic acid (caprylic acid), decanoic acid (capric acid), oleic acid, oxalic acid, and glycine—were found to have the strongest discriminatory potential for separating the HCC and cirrhosis groups, and ROC curve analysis revealed that oleic acid, octanoic acid and glycine had higher positive predictive value than AFP. The gene discussed is AFP; the disease is hepatocellular carcinoma.