We choose CD44v10 because it is hardly expressed in HSC (M.Zöller, unpublished), but expressed in some leukemia [46], particularly in cutaneous lymphoma [31], Hodgkin’s disease [34] and multiple myeloma [35] and because it is an OPN ligand [unpublished finding], where OPN is important in guiding HSC from the osteogenic to the vascular niche [47-49]. This evidence concerns the gene SPP1 and leukemia.