Doctors are not sure what causes leukaemia. It is likely that abnormal genes play a part. One type of leukaemia, chronic myeloid leukaemia (CML), is often caused by an abnormal chromosome. It is also likely that a person's chances of getting leukaemia are affected by where they live, where they work, what they eat and more.
In acute lymphoblastic leukaemia (ALL), it's thought that the response of the immune system to certain infections may affect development in some people.
Risk factors for leukaemia
While the exact causes of leukaemia are unclear, some things are known to increase the risk of developing leukaemia. These are called 'risk factors' and include:
- smoking tobacco
- exposure to high levels of radiation, for example from having radiation therapy for another type of cancer
- exposure to certain chemicals, for example benzene
- previous cancer treatment with chemotherapy or radiotherapy
- having certain genetic disorders, for example Down syndrome
- certain viral infections, for example human T-cell leukaemia virus
- a personal history of blood disorders, for example myelodysplastic syndrome
- having someone with leukaemia in the family
You can lower your risk of getting cancer by eating well, exercising regularly, giving up smoking and cutting back on alcohol. But in many cases, there is no known way to prevent leukaemia.
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Last reviewed: February 2019