What is myelofibrosis?1

Myelofibrosis (MF) is a rare type of blood cancer that typically develops slowly and tends to affect the over 50s. In MF, scar tissue develops in the bone marrow, where blood cells are produced. This disrupts the production of blood cells and can lead to anaemia and fatigue.1,2,3 The spleen and liver may start producing red blood cells instead. However, these organs are inefficient at producing blood cells and may become enlarged.2,3 This can reduce the number of blood cells and exacerbate anaemia.2,3

What causes myelofibrosis?

Myelofibrosis is usually caused by a genetic mutation. The mutations in MF are usually acquired during life rather than inherited from parents and are unlikely to be passed on to children.2,4 Mutations in the JAK2 gene account for 50–65% of MF cases in the UK, while mutations in the CALR gene are associated with a further 25–30% of patients. Other, less common mutations may also contribute to MF.2,4

What are the symptoms of MF?

The main symptoms of MF are associated with low levels of blood cells.3

  • Tiredness
  • Feeling breathless
  • Fevers and night sweats
  • Losing weight
  • Itchy skin (often after a warm bath or shower)
  • Achy or tender bones and joints
  • Discomfort in the tummy area
  • Feeling full soon after beginning to eat
  • Bleeding or bruising more easily
  • Having infections one after another

How is myelofibrosis diagnosed?

Myelofibrosis is usually diagnosed by a haematologist after a series of tests:3,5

  • A full blood test to identify any unusual blood cells
  • Genetic testing for known mutations that cause MF
  • A bone marrow biopsy
  • Imaging tests, such as an MRI, to check for an enlarged spleen or liver

What is the goal of treatment for myelofibrosis?3,4,6,7

Unfortunately, MF can’t be cured with conventional therapies. The only way to cure MF is with a stem cell transplant, which can be a risky procedure and is not available to all patients. MF symptoms can have a significant impact on patients’ quality of life.7 For this reason, the goal of treatment is to relieve symptom burden and slow disease progression.4 Treatments may be tailored to manage patients’ individual needs based on their symptom type and severity, and the effect on quality of life.

Since MF typically develops slowly, some patients may not experience burdensome symptoms at diagnosis. These patients and their doctors may decide not to receive active treatment and instead opt to be monitored on a ‘watch and wait’ programme.



  1. Leukemia and Lymphoma Society. Myeloproliferative neoplasms. Myelofibrosis. Available at: https://www.lls.org/myeloproliferative-neoplasms/myelofibrosis/signs-and.... Last accessed April 2020.
  2. Blood Cancer UK. What is myelofibrosis (MF)? Available at: https://bloodcancer.org.uk/understanding-blood-cancer/myeloproliferative.... Last accessed April 2020.
  3. Macmillan Cancer Support. Myelofibrosis. Available at: https://www.macmillan.org.uk/cancer-information-and-support/blood-cancer.... Last accessed April 2020.
  4. MPN Voice. Myelofibrosis. Available at: https://www.mpnvoice.org.uk/about-mpns/questions-about-mpns/myelofibrosi.... Last accessed April 2020.
  5. Blood Cancer UK. Symptoms and diagnosis of myelofibrosis (MF). Available at: https://bloodcancer.org.uk/understanding-blood-cancer/myeloproliferative.... Last accessed April 2020.
  6. Blood Cancer UK. Treatment and side effects for myelofibrosis (MF) Available at: https://bloodcancer.org.uk/understanding-blood-cancer/myeloproliferative.... Last accessed April 2020.
  7. Mesa R, et al. Myeloproliferative neoplasms (MPNs) have a significant impact on patients’ overall health and productivity: the MPN Landmark survey. BMC Cancer. 2016;16:167.
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ONC20-C055 June 2020

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