Background Osteosarcoma(OS)is the most common primary malignant tumor of bone.Mouse models of human OS can invariably provide greater insight into the complex mechanisms that underlie the development and pathogenesis of this aggressive tumor.Bioluminescence technology favored tracing cancer cells in vivo.In this study,an OS model was described and evaluated using human OS cell line,Saos2,labeled with luciferase(Saos2-luc).Methods Saos2 cells were infected by lentivirus loading a firefly luciferase gene.Luciferase expression of Saos2-luc cells was characterized both in vitro and in vivo.Specific biologic and oncologic features of Saos2-luc cells were analyzed.The OS was established as orthotopic xenografts in nude mice.Both orthotopic tumors and spontaneous lung metastasis were analyzed.Results Tumorigenesis and spontaneous lung metastasis in nude mice could be monitored in vivo through in vivo imaging system.The enhancement in proliferation,migration and invasion abilities and the attenuation in adhesion ability were observed in Saos2-luc cells compared with Saos2 cells.Furthermore,there were the up-regulation of Osteocalcin,CCR10,CXCR1 and ID1 and the down-regulation of ALP,collagen Ⅰ,CCR1,CCR3,CXCR3,NID and N-cadherin in Saos2-luc cells compare to Saos2 cells.The rate of spontaneous lung metastasis in Saos2-luc cells was higher than that in Saos2 cells,although without significant difference.Conclusions Lentivirus transfection may cause alteration of gene expression profiles and further biological functions.This model can be used in the elucidation of molecular mechanisms of tumorigenesis and the screening of new therapeutic agents.