ERBB2 and osteosarcoma: This was carried out by evaluating the expression of two kinds of molecules on cells derived from apheretic procedures: (a) Bone Sialoprotein (BSP) and Osteocalcin that are produced by bone cells, histotypically similar to osteosarcoma cells; (b) oncogenes like MET or ErbB2, frequently overexpressed in osteosarcomas.