• Juvenile Myelomonocytic Leukemia (JMML) Overview

    Similar in some ways to chronic myelogenous leukemia, juvenile myelomonocytic leukemia (JMML) is rare a type of leukemia in which bone marrow production becomes very disregulated. The bone marrow produces immature myelocytes and monocytes, types of infection-fighting white blood cells, which crowd out healthy cells. 

    JMML generally causes a more severe disruption in blood counts early in the disease than CML and it is not as responsive to treatment.

    JMML treatment at Dana-Farber/Boston Children's

    Patients with juvenile myelomonocytic leukemia are treated at Dana-Farber/Boston Children's Cancer and Blood Disorders Center through the Leukemia Program. Continue reading to learn more about JMML or visit the Leukemia Program homepage to learn about our expertise and treatment options for this condition.

    Symptoms & Diagnosis

    Children usually don’t have any symptoms in the early stages of JMML. When they do occur, a child may experience them over a period of months or even years.

    The most common symptoms of CML include:

    • General fatigue
    • Weakness
    • Recurrent infections
    • Bone and joint pain from overcrowded bone marrow
    • Swollen lymph nodes in the groin, chest or neck

    JMML is often diagnosed during a routine blood test conducted for other reasons. Other diagnostic tests include:

    • Bone marrow aspiration and biopsy
    • Lymph node biopsy
    • Complete blood count
    • Chromosomal analysis, which can help distinguish JML from other leukemias
    • Blood chemistry tests
    • Liver and kidney function tests
    • Lumbar puncture (spinal tap)

    After all tests are completed, doctors will be able to outline the best treatment options.

    Treatment & Care Options

    Treatment options for JMML may include (alone or in combination):

    Progressive or Recurrent Disease

    If JMML recurs, the treatment plan often includes targeted therapy (chemotherapy drugs that specifically attack a molecular pathway required to keep a tumor growing), chemotherapy and immunotherapy (treatment that stimulates the immune system to reject and destroy a tumor). Recurrent JMML may come back in the blood or bone marrow, or other parts of the body, such as the central nervous system and brain.

    Long-term Outlook

    Despite advances in treatment, JMML remains difficult to cure. Without treatment, the five-year survival rate is dismal (about 5%). Stem cell transplantation has proven to be a successful treatment; however, the relapse risk is significant—about 50 percent—following a transplant. If JMML recurs after a stem cell transplant, a second transplant may be done.
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