What is blood cancer?

There are different types of blood cancer, including:

• leukaemia
• lymphoma
• myeloma
• myelodysplastic syndromes (MDS)
• myeloproliferative neoplasms (MPN)

They each have different symptoms, treatments and prognoses.

If you've recently been diagnosed with any type of blood cancer, order our free booklet 'Your blood cancer diagnosis - what happens now?'. It tells you the key things to know about blood cancer, including tips from other people who've been diagnosed.

If someone you love has been diagnosed, you might find our information for family and friends helpful. It covers how to support someone with blood cancer, practical tips, coping with your own emotions, and lots of real stories from other friends and family members.

You might see blood cancers described as:

• acute – this means a fast-growing cancer. If you have an acute lymphoma, it will also be referred to as ‘high grade’.
• chronic – this means a slower-growing cancer. If you have a chronic lymphoma, it will also be referred to as ‘low grade’.

Some types of blood cancer affect children. Symptoms and treatment can be different between children and adults. We have more information about childhood leukaemia.

All blood cancers are caused by changes in DNA within blood cells. This causes the blood cells to start behaving abnormally.

In almost all cases, these changes are linked to things we can’t control. They tend to happen during a person’s lifetime, and they are not usually hereditary. This means it is unlikely that you have inherited a blood cancer from a family member, or that you will pass one on to any children you have.

However, there is some evidence that developing some blood cancers may increase the risk of people related to you developing the same kind. If this is the case, you and your family should be offered genetic testing.

Scientists are doing more research all the time to understand the genetic causes of blood cancer.

Although we don’t always know exactly why someone has developed blood cancer, there are things that can affect your overall risk, including:

• age
• sex
• ethnicity
• radiation or chemical exposure
• lifestyle activities such as smoking
• some infections and infectious diseases
• some health conditions and treatments.

How these factors affect your risk depends on the type of blood cancer you have and your overall general health and fitness. You can read more about risk factors on another page, and your doctor will be able to tell you more about your own personal risk.

Unlike some other cancers, lifestyle factors such as diet and exercise have little effect on your risk of developing blood cancer.

However, a healthy lifestyle can significantly reduce your risk of other types of cancer and other diseases. Staying healthy and active can also help you to cope with treatment and recovery, if you do develop a blood cancer or any other health condition.

Your body is made up of trillions of tiny building blocks called cells. Cells make up every part of your body, including your blood.

The cells in your body are constantly dying and being replaced. This is how your body grows and repairs itself. Normally, cells divide (split) in a controlled way, to make new cells when needed.

DNA is a substance within your cells, which controls how cells develop, behave and die. If something goes wrong with the DNA inside a blood cell, the blood cell may not develop or work properly. It may not die when it should, or it might divide and multiply too quickly. This can all lead to developing blood cancer.

In blood cancer, abnormal blood cells can keep multiplying. They may not be working properly, and they may prevent healthy blood cells from growing or working too. This can stop your blood doing the things it normally does to keep you healthy, like fighting off infections or helping to repair your body.

We have a separate page about blood cells if you want to find out more.

Last full review April 2026. Next full review due April 2029. We may make factual updates to the information between reviews.

We would like to thank Consultant Haematologist Dr Priya Sriskandarajah for checking the clinical accuracy of this information.