Evidence for the osteosarcoma stem cell.

Osteosarcoma is a highly malignant bone tumor of children and young adults. Cytotoxic chemotherapy combined with aggressive surgery only has a 60% survival rate. Historically, chemotherapy has been developed assuming that all cells within a particular cancer are clonal and near identical. Appreciating the now apparent functional heterogeneity of osteosarcoma cells within and between individual tumors will likely be critical in developing much needed novel effective therapies. The foundation for this heterogeneity may lie in the so called "cancer stem cell" or tumorigenic cell of origin. In this brief review, we will examine the evidence for the existence of this cell and its potential importance for future therapies.