Leukemia, Chronic Myelogenous
- Chronic myelogenous leukemia (CML) is a myeloproliferative neoplasm characterized by clonal proliferation of myeloid precursors in the bone marrow with continuing differentiation into mature granulocytes.
- The hallmark of CML is the Philadelphia chromosome (translocation t[9;22]).
- Natural history of the disease evolves in three clinical phases: a chronic phase, an accelerated phase, and a blast phase or crisis (can transform to acute myeloid leukemia [80%] or acute lymphoblastic leukemia [20%]).
- Per year, 1.9 cases/100,000 persons
- Median age at diagnosis: 65 years
- Predominant sex: male > female (1.7:1)
Accounts for 15–20% of adult leukemias
Etiology and Pathophysiology
Philadelphia chromosome is a balanced translocation between BCR (on chromosome 22) and ABL (on chromosome 9) genes t(9;22)(q34;q11). This fusion gene, BCR-ABL, codes for an abnormal, constitutively active tyrosine kinase that affects numerous signal transduction pathways, resulting in uncontrolled cell proliferation and reduced apoptosis.
Acquired genomic changes
Ionizing radiation exposure (uncommon)
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