What is Chronic Myelomonocytic Leukemia?

Chronic myelomonocytic leukemia (CMML) is cancer of the blood. CMML is considered to be one of the myelodysplastic/myeloproliferative neoplasms (MDS/MPN), a type of chronic blood cancer in which a person's bone marrow does not make blood effectively. MDS/MPN have both "dysplastic" and "proliferative" features that cannot be classified as either myelodysplastic syndromes (MDS) or myeloproliferative neoplasms (MPN), and for this reason have been categorized as an overlap syndrome with its own distinct characteristics (MDS/MPN).

Normally, our bone marrow makes the blood cells that circulate in our blood. It is within the bone marrow that blood stem cells (immature cells) become mature blood cells over time. In people with MDS/MPN, some of the immature blood cells never fully develop into mature blood cells.

In people with CMML, their bone marrow makes too many white blood cells (monocytes). CMML should not be confused with CML, or chronic myelogenous leukemia, which is caused by a specific genetic change called the Philadelphia chromosome, and is treated very differently.

In CMML, there is no Philadelphia chromosome; instead CMML is caused by different genetic alterations.

Symptoms of CMML

Some people with CMML never experience symptoms, and are diagnosed during routine blood tests. Others do experience symptoms.

Symptoms of CMML may include:

  • Enlarged spleen
  • Feeling tired, shortness of breath
  • Frequent infections
  • Bleeding or bruising easily
  • Weight loss without trying

Other Names for CMML

Chronic myelomonocytic leukemia, MDS/MPN

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