Myeloproliferative neoplasms (MPN)

What is MPN?

Myeloproliferative neoplasms (MPN) are cancers that start in the bone marrow, where blood cells are made.

In MPN, the bone marrow makes too many of one or more types of blood cells (red blood cells, white blood cells and/or platelets). These cells change the thickness of the blood. Sometimes they don’t work properly. They also crowd the bone marrow and then it can’t make enough healthy blood cells.

There are seven types of MPN, diagnosed using blood tests and a bone marrow biopsy. Some forms can transform into other types of MPN or into acute myeloid leukaemia.

Symptoms depend on which type of MPN you have. Symptoms common to the types are: fatigue, weakness, weight loss, enlarged spleen (splenomegaly), bruising and bleeding, night sweats, pain in bones or joints.

In most cases we don’t know what causes MPN. There is usually a mutation in (change to) the genetic material of growing blood cells. There’s no way to prevent MPN and you can’t catch it or pass it on.

How common is MPN?

Myeloproliferative neoplasms are a rare group of blood cancers. Polycythaemia vera is diagnosed in an estimated 250 Australians each year, essential thrombocythaemia around 200 and myelofibrosis an estimated 150. The rarer sub types of MPN, as a group, are diagnosed in less than 50 Australians per year.

Who gets MPN?

Most people with an MPN have no family history.  MPN is more commonly diagnosed in people over the age of 50 although it can rarely occur in younger people, even very rarely in children.

What causes MPN?

The exact cause of MPNs remain unknown but there are likely to be a number of factors involved. That’s why MPNs, like most leukaemias and other cancers, become more common as we get older. A mutation of a particular gene (a segment of DNA that makes proteins) known as Janus kinase 2 (JAK2) is found in a large proportion of people with MPNs. The exact meaning of this mutation remains unclear but it appears to play a role in the overproduction of blood cells seen in these disorders. The discovery of a mutation in the JAK2 gene is important because it is likely to have a significant impact on the way MPNs are diagnosed and treated.

Long-term exposure to high levels of benzene or very high doses of ionising radiation may increase the risk of myelofibrosis in a small number of cases. Around one third of people with myelofibrosis have been previously diagnosed with polycythaemia or essential thrombocythaemia.

What are the symptoms of MPN?

Many people have no symptoms when they are first diagnosed with an MPN and the disease is picked up accidentally during a routine blood test or physical examination. In other cases, people go to see their GP because they have some troubling symptoms of their disease. When symptoms do occur, they develop gradually over time. Common symptoms include:

• headaches
• blurred vision
• fatigue
• weakness
• dizziness
• itchiness (pruritus)
• night sweats
• raised blood pressure (hypertension).

Other symptoms experienced in MPN are a result of the affected cell involved with the MPN.

MPN webinar – MPN Awareness Day 2020

In the video below, MPN experts and people with lived MPN experience discuss some of the latest MPN treatment updates including:

Prof Andrew Perkins from Monash University.
Topic: Current clinical and research interests – rundown on how diagnosis and treatment is progressing and emerging therapies.

Prof Wendy Erber from University of Western Australia.
Topic: Why do Myeloproliferative Neoplasms Progress to Fibrosis?.

Prof Peter Baade from Cancer Council QLD.
Topic: How does the burden of MPN in Australia vary by where people live?

Helen Williams from Sydney. Helen is newly diagnosed with PV and discusses her experience from a patient perspective.

Developed by the Leukaemia Foundation in consultation with people living with a blood cancer, Leukaemia Foundation support staff, haematology nursing staff and/or Australian clinical haematologists. This content is provided for information purposes only and we urge you to always seek advice from a registered health care professional for diagnosis, treatment and answers to your medical questions, including the suitability of a particular therapy, service, product or treatment in your circumstances. The Leukaemia Foundation shall not bear any liability for any person relying on the materials contained on this website.