CD34 and chronic myelogenous leukemia, BCR-ABL1 positive: With the aim of assessing the prognostic importance of changes in the length of telomeres in leukemic leukocytes of patients with CML and discovering the mechanisms responsible for the dynamism of changes in telomere length, we have conducted research on leukocytes including CD34+ primary leukemic cells, comprising both leukemic stem and progenitor populations isolated from patients at the CML-CP and CML-BP stages of the disease.