Our results indicate that developed scFvs and scFvs-Fc reduce the in vitro proliferation of FGFR1-expressing mouse fibroblast NIH/3T3cells, FGFR1-transfected BaF3 cells, and most importantly G-292 human osteosarcoma cancer cells. The gene discussed is FGFR1; the disease is osteosarcoma.