As shown in Fig. 4g, h, we observed impaired TG hydrolysis and FFA oxidation pathways in HCC tissues, manifested as significantly reduced expressions of ATGL, MAGL, CPT1α, peroxisome proliferator-activated receptor-α (PPARα), PPAR-γ coactivator 1α, ACADM, and 5′-AMP-activated protein kinase (AMPK), the key regulator in FFA metabolism. The gene discussed is PNPLA2; the disease is hepatocellular carcinoma.