CD44 and osteosarcoma: We next assessed the percentage of CD47+ cells within the CD44, [a well-established osteosarcoma cancer stem cell (CSC) markers [11], subpopulation in a set of ten primary patient-derived osteosarcoma cancer cell cultures, and as shown in Figure 1D, the majority of CD44+ cells expressed CD47 albeit with different percentages (ranging from 80% to 99%), which indicated that which indicated that osteosarcoma CSCs are mostly confined to CD47+ cells.