Furthermore, remodeling of BM niche to favor tumor progression over normal cells (a niche-dependent with niche alteration mechanism) has been recently suggested by elegant experimental chronic myeloid leukemia models where leukemic cells decreased expression of CXCL12 concomitant to increased G-CSF production, impairing normal hematopoiesis and facilitating leukemia growth (22, 28). This evidence concerns the gene CXCL12 and leukemia.