Leukaemic stem cells (LSC) in CML are characterized by their self‐renewal ability and their capacity to propagate the CML for unlimited time periods.69, 70, 71, 72 Contrasting normal stem cells, CML LSC are less capable of homing into BM niches, presumably because of altered interactions with chemotactic cytokines, such as stroma cell‐derived factor‐1 (SDF‐1).73, 74, 75 As a result, CML LSC are considered to redistribute into the blood at high rates, which results in a persistent, marked, extramedullary spread of myelopoietic stem and progenitor cells. This evidence concerns the gene CXCL12 and chronic myelogenous leukemia, BCR-ABL1 positive.