CXCR4 and osteosarcoma: Although we are currently unable to dissect the specific mechanisms by which HIF-1α upregulates CXCR4 in vivo, we have identified that the hypoxia-HIF-1α-CXCR4 pathway may regulate trafficking and localization of SOSP-9607 cells and may represent a target for novel therapeutic strategies for human osteosarcoma.