PPARA and hepatocellular carcinoma: Functional enrichment analysis of each malignant cells cluster showed intratumoral heterogeneity of HCC, such as HCC_NTS and HCC_HRG specifically enriched in Oxidative phosphorylation, Notch signaling pathway, MAPK signaling pathway, and PPAR signaling pathway, suggesting that the enrichment of these pathways contributes to the high heterogeneity of cell clusters (Fig. 2D).