Concentrations of two major niche factors, SCF and CXCL1237–40, were higher in the BM fluid than those in the blood plasma but did not increase upon anemia induction (Fig. 3a, b), indicating that proliferation and altered lineage-choice were not due to the effect of EPO or SCF/CXCL12. This evidence concerns the gene CXCL12 and anemia (phenotype).