The biologic similarity between canine and human osteosarcoma makes it a disease model that holds promise for translational research possibilities. The phenotypic and functional differences the investigators expect to find in canine and human monocytes between normal and osteosarcoma subjects in this pilot work will allow us to launch a program of investigations to further their understanding as to what characteristics are associated with improved survival in canine and human osteosarcoma. Such data will represent the foundation upon which the investigators can plan future investigations designed to exploit the potential anti-tumor capabilities of monocytes and macrophages in canine and human osteosarcoma.