SPP1 and hepatocellular carcinoma: The heatmap visualized showed that overexpressed GP73 HCC cell clusters interacted with endothelial cells through multiple angiogenic receptor–ligand reactions, including CXCL5–ACKR1, VEGFA–VEGFR1/R2, TGFB1–(TGFBR1 + TGFBR2), SPP1–(ITGAV + ITGB1), and ANGPTL4–CDH5 (Fig. 2E).