BCR and chronic myelogenous leukemia, BCR-ABL1 positive: In line with this, a recent clinical trial compared the telomere length of non-leukemic BCR ABL-CD34+CD38 negative hematopoietic stem cells (HSC) to that of their BCR-ABL positive leukemic stem cell (LSC) derived from the bone marrow of CML patients at diagnosis [168].