FAS and hepatocellular carcinoma: Because 18F-fluorodeoxyglose (18F-FDG) shows mitigated performance to detect HCC (10, 11) but excellent specificity for HCC metastases (9), PET radiotracers of fatty acid synthase (FAS) have been proposed as complements, such radiolabeled choline, the most widely used FAS-targeted radiotracer in clinical practice (12, 13).