PPARA and hepatocellular carcinoma: Interestingly, shared down-regulated pathways in C1 subtype, for both HCCs and CCAs, included peroxisomes, glycine/serine/threonine metabolism, and PPAR signaling pathways (Supplementary Figures S1B and S2B), of which PPARγ has been demonstrated to display inhibitory effects on HCC metastasis [74,75].