To identify which FAS1domain mediated human osteosarcoma cells metastasis, we cloned the total gene of βig-h3 (WT) and its four segments of highly conserved sequence, the first FAS1domain (D-I), the second FAS1domain (D-II), the third FAS1domain (D-III) and the fourth FAS1domain (D-IV) and then we transfected them into Saos-2 cells. This evidence concerns the gene TGFBI and osteosarcoma.