Myeloproliferative neoplasms

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Myeloproliferative neoplasms (MPNs) are a group of blood diseases where the bone marrow makes too many of one or more types of blood cells. An MPN starts when a single blood stem cell changes (mutates) and reproduces. Certain MPNs may develop into acute myeloid leukemia (AML).

MPNs are classified as blood cancers because the blood cells are being made in an uncontrolled way. But MPNs often develop and progress slowly (called chronic) so they need only mild treatments.

The main types of MPNs are:

  • polycythemia vera
  • essential thrombocythemia
  • myelofibrosis

Chronic myeloid leukemia (CML) is the most common type of leukemia and is also considered an MPN. Find out more about chronic myeloid leukemia (CML).

There are rare types of MPNs that do not have a standard treatment, such as chronic neutrophilic leukemia and chronic eosinophilic leukemia.

There are some MPNs that also have features of myelodysplastic syndromes (MDSs). These are called myelodysplastic/myeloproliferative neoplasms. They include chronic myelomonocytic leukemia (CMML) and atypical chronic myeloid leukemia (aCML).

Expert review and references

  • Kareem Jamani, MD, LMCC, FRCPC
  • Cancer Research UK. Myeloproliferative Neoplasms. 2020:
  • Leukemia and Lymphoma Society. Myeloproliferative Neoplasms: Polycythemia Vera, Essential Thrombocythemia and Myelofibrosis. Rye Brook, NY: 2021:
  • PDQ Adult Treatment Editorial Board. Chronic Myeloproliferative Neoplasms Treatment (PDQ®) – Health Professional Version. Bethesda, MD: National Cancer Institute; 2020:

Polycythemia vera

Polycythemia vera (PV) develops when the body makes too many red blood cells and sometimes too many white blood cells or platelets. Treatments for PV include a phlebotomy and supportive therapy.

Essential thrombocythemia

Essential thrombocythemia (ET) develops when the body makes too many platelets. ET can be treated with observation and drug therapy.


Myelofibrosis is a blood disease where scar tissue builds up in the bone marrow that causes abnormal amounts of healthy blood cells. Drug therapy is the main treatment for myelofibrosis.

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