We have previously isolated fetal liver kinase-1-positive (Flk1+) mesenchymal stem cells (MSCs) carrying the BCR/ABL fusion gene from the bone marrow of Philadelphia chromosome-positive (Ph+) patients with hemangioblast property and they were proved to be the cancer stem cells in CML which differ from the normal MSCs4. This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.