CML

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  • CML
    • myeloproliferative condition
    • has 25% risk/year of transforming to acute leukemia (blastic transformation).(MCQ)
    • Signs and symptoms
      • Chronic phase:
        • WBC counts increase, spleen and liver enlarge
      • Accelerated phase:
        • RBC, platelets decrease
        • symptoms include bone pain,fever, night sweats, and weight loss
      • Blastic phase:
        • Peripheral blood and marrow are filled with rapidly proliferating leukemic blast cells.
    • Diagnosis
      • Examining the peripheral blood film shows increased myeloblasts and basophils, white blood cells
      • Leukocyte alkaline phosphatase is low in CML cells. (MCQ)
      • 90% have Philadelphia chromosome t(9;22). (MCQ)
    • Treatment
      • Allogenic bone marrow transplant treatment of choice for younger patients(MCQ)
      • Imatinib inhibits Philadelphia chromosome and induces indefinite remission (MCQ)
      • Chemotherapy
        • busulfan and hydroxyurea (MCQ)
          • for those that cannot have BMT (chronic phase)
        • vincristine and prednisone (MCQ)
          • for those in the accelerated/blastic phase.
    • Clinical Pearls :
      • Better prognosis of CML is associated with: (MCQ)
        • Young age(<40)
        • No thrombocytopenia
        • Early stage
        • Low percentage of blasts
      • 90% of patients with CML have the Philadelphia chromosome t(9;22). (MCQ)
      • Philadelphia chromosome
        • a reciprocal translocation between the long arms of chromosomes 9 and 22(MCQ)
        • A large portion of 22q is translocated to 9q, and a smaller piece of 9q is moved to 22q.
        • The portion of 9q that is translocated contains abl, a protooncogene that is the cellular homolog of the Ableson murine leukemia virus.
        • The abl gene is received at a specific site on 22q, the break point cluster (bcr). (MCQ)
        • The fusion gene bcr/abl produces a novel protein that differs from the normal transcript of the abl gene in that it possesses tyrosine kinase activity (a characteristic activity of transforming genes). (MCQ)
      • Rarely, the patient will present with a clinical syndrome related to leukostasis(MCQ)
        • Presents with blurred vision, respiratory distress, or priapism.
        • white blood count in these cases is usually greater than 500,000/mcL.
      • the spleen is enlarged in CML (often markedly so),
      • sternal tenderness may be present as a sign of marrow overexpansion.
      • The peripheral blood is characteristic
        • The myeloid series is left-shifted, with mature forms dominating and with cells usually present in proportion to their degree of maturation.
        • Blasts are usually less than 5%.
        • Basophilia and eosinophilia of granulocytes may be present. (MCQ)
        • At presentation, the patient is usually not anemic.
        • Red blood cell morphology is normal, and nucleated red blood cells are rarely seen.
        • The platelet count may be normal or elevated (sometimes to strikingly high levels).
      • The hallmark of the disease is that the bcr/abl gene is detected by the polymerase chain reaction (PCR) test in the peripheral blood.
      • A bone marrow examination
        • not necessary for diagnosis
        • it is useful for prognosis and for detecting additional chromosomal abnormalities in addition to the Philadelphia chromosome.
      • Blast phase CML is diagnosed when blasts comprise more than 30% of bone marrow cells.
        • Treatment is usually not emergent even with white blood counts over 200,000/mcL, since the majority of circulating cells are mature myeloid cells that are smaller and more deformable than primitive leukemic blasts(MCQ)
      • A “major cytogenetic response” is identified when < 35% of metaphases contain the Philadelphia chromosome
      • A “complete cytogenetic response” indicates the absence of the abnormal chromosome by standard cytogenetic testing.
      • The current goal of therapy is to achieve a “good molecular response,” with at least a 3-log reduction in bcr/abl level. (MCQ)
      • Patients with an accelerated phase of CML should initially be treated with imatinib, , or dasatinib, but should be considered for allogeneic transplantation
      • The only proven curative therapy for CML is allogeneic bone marrow transplantation. (MCQ)
      • The best results (80% cure rate) of BMT are obtained in patients (MCQ)
        • who are under 40 years of age
        • transplanted within 1 year after diagnosis from HLA-matched siblings


Chronic Myelogenous Leukemia – CRASH! USMLE Step 2 and 3
(Disclaimer: The medical information contained herein is intended for physician medical licensing exam review purposes only, and are not intended for diagnosis of any illness. If you think you may be suffering from any medical condition, you should consult your physician or seek immediate medical attention.)
Chronic Myeloid Leukemia.
Chronic Myelogenous Leukemia
Chronic Myelogenous Leukemia
Chronic myelogenous leukemia (CML)
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CML – Animation

CML – Part Two

Histopathology Blood –Chronic myelogenous leukemia
Histopathology Blood –Chronic myelogenous leukemia