CSPG4 and osteosarcoma: CSPG4 is a promising target antigen highly expressed in multiple tumor types, including melanoma, glioblastoma, breast carcinomas, osteosarcoma and hematologic cancers.25,35 Originally believed to have a very limited distribution in normal adult tissues,36 CSPG4 expression has since been observed in a wider range of organs, but preferentially associated with progenitor cell phenotypes.37 Accordingly, we detected low to moderate expression of CSPG4 in some human anatomical locations including the CNS, spleen, bone marrow and endocrine organs like the thyroid gland and adenohypophysis.