SDC2 and osteosarcoma: Different cellular signaling pathways regarding growth factor between two mitochondria-related signature score groups of osteosarcoma cells and microenvironment cells are shown in Figures 6E, F, in which ITGB2, SDC2, PGF, and TGFB1 were the most active signaling pathways in osteosarcoma cells with the high mitochondria-related signature score.