Among these 114 proteins, thirteen proteins, including CHEK2, TP53, RB1, VEGFA, EGFR, RUNX2, MDM2, MMP2, MET, DHFR, TNFRSF11A, JUN, and RFC1, were reported to participate in the pathological process of osteosarcoma directly. This evidence concerns the gene DHFR and osteosarcoma.