Chronic Myelogenous Leukemia November 2001

Ahmed Galal, MD, MSc, FRCPC
Fellow in Allogeneic Bone Marrow Transplant,
University Health Network
Princess Margaret Hospital,
Toronto, ON.

Jeffrey Lipton, PhD, MD, FRCPC
Chief, Allogeneic Bone Marrow Transplant Program,
Princess Margaret Hospital,
Head, Chronic Myeloid Leukemia Group,
Associate Professor of Medicine,
University of Toronto,
Toronto, ON.


Chronic myelogenous leukemia (CML), in addition to polycythemia rubra vera and essential thrombocytosis, are the most commonly diagnosed forms of the myeloproliferative disorders.1-5 These diseases share several distinct features:

  • They are clonal disorders of hema-topoiesis that arise in a hematopoietic stem or early progenitor cell;
  • They are characterized by the dysregulated production of a particular lineage of mature myeloid cells with fairly normal differentiation;
  • They exhibit a variable tendency to progress to acute leukemia.

Cytogenetic studies of bone marrow and peripheral blood in the benign myeloproliferative disorders are usually normal. However, CML is invariably associated with an abnormal chromosome known as the Philadelphia chromosome.6 CML accounts for 15-20% of adult leukemias. It has an annual incidence of 1 to 2 cases per 100,000, with a slight male predominance.