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Figure 2. Anatomical and functional bidirectional gut-microbiota-liver axis in HCC. Schematic diagram illustrating key communication pathways with simplified components. Solid purple tube/arrows indicate the portal vein, transporting gut-derived signals; thin green arrows indicate lymphatic pathways; and solid green tube/arrows indicate the biliary tract pathway. Character definitions: Red spiky spheres (LPS); Orange triangles (MAMPs); Blue/green polygons (Gut-derived metabolites); Yellow spheres (Bile acids). Specific physiological mechanisms and cellular signaling details are provided in the corresponding text. HCC: Hepatocellular carcinoma; LPS: lipopolysaccharide; MAMPs: microbiota-associated molecular patterns; FXR: farnesoid X receptor; TGR5: Takeda G protein-coupled receptor 5.