What causes blood cancer?

On this page we talk about things like blood cells, genes, chromosomes and DNA. Read more about what these terms mean below.

Blood cells

There are three main types of cells in your blood:

• red blood cells, which help carry oxygen around your body
• white blood cells, which help to fight off infection
• platelets, which help your blood to clot.

Different types of blood cancer affect different types of blood cell.

We have a separate page about blood cells if you are interested in finding out more.

DNA

DNA (deoxyribonucleic acid) is the genetic code that controls how the cells in our body grow and develop. Your DNA is usually completely unique, unless you are an identical twin.

Chromosomes

DNA is packaged up and stored in structures inside cells called chromosomes. Almost all of our cells, including all white blood cells, contain DNA arranged in 23 pairs of chromosomes.

Genes

Genes are short sections of DNA which control specific functions of cells. Every human has around 20,000 genes. Some of our genes therefore provide the information needed for our blood cells to grow and divide.

Genetics

Genetics is the study of a particular gene or group of genes.

Genomics

Genomics refers to your entire set of DNA and how all your different genes function and interact with one another.

Blood cancer is a type of cancer that affects your blood cells. There are lots of different types of blood cancer, and all of them are caused by genetic changes in our DNA. You may also hear these changes called variants or mutations.

Everybody will have changes in their genes. Sometimes, the instructions for these changes will be present from birth, and will therefore be in all of our cells. But, the majority of changes happen during our lifetime to only some of our cells, for reasons we don’t quite understand yet. Some of these changes may be caused by activities such as smoking, which can increase the chance of experiencing genetic changes.

The longer we live, the more changes to our genes we will typically get. Many gene changes are harmless, but some of them can increase the chance of developing diseases such as blood cancer.

Usually, the genes in our DNA tell our blood cells how to grow, divide and reproduce properly. But, if something goes wrong with this process, normal healthy blood cells can turn into cancer cells. These abnormal cells can then grow and divide to produce even more cancer cells.

Most cancers are believed to happen as a result of the genetic changes that occur during our lifetime. This means that the majority of people who develop blood cancer will not have a family history of blood cancer. Even if more than one person in your family has been diagnosed with blood cancer, it doesn’t mean there is a hereditary link. You can read more about family history and possible hereditary connections further down this page.

If you or your doctor thinks there may be a chance you have blood cancer, there are lots of different tests you might need to have.

Genetic tests can help doctors to diagnose the type of blood cancer you have. Scientists conducting the tests will analyse proteins, chromosomes, DNA and genes in your cells and look for any changes that have occurred.

After diagnosis, genetic tests may also be used to:

• help determine your prognosis
• help predict what treatment might work best for the type of blood cancer you have
• help show how your body is responding to treatment of the cancer itself
• help detect any evidence of relapse
• help establish whether there is any possibility that the blood cancer is hereditary, and therefore whether any of your relatives are at increased risk of developing the same or a similar disease.

You may hear genetic testing referred to as cytogenetics, cytogenetic testing, FISH, molecular genetics, or molecular testing.

Two common types of genetic tests that are looking for “big changes” on a chromosome level are karyotyping and fluorescence in situ hybridisation (FISH) tests. We have more information about these tests in the menu below.

The vast majority of people who develop a blood cancer will not have another member of the family who also has a blood cancer. Therefore, if you have been diagnosed with a blood cancer, it is very unlikely that any of your brothers, sisters or children will develop a blood cancer. However, despite the chances of your family members developing a blood cancer being very low, they have a slightly higher chance than members of the general public. More research is being done to investigate and understand any potential connections.

If you have been diagnosed with a blood cancer and are worried that it was passed down through your family, or if you’re worried about passing it on to your children, speak to your doctor or hospital team. They will be able to tell you more about any potential risk factors, and explain what they know about the type of blood cancer you have.

If your genetic tests reveal that there may be a hereditary gene involved in your blood cancer diagnosis, you and your family may be referred for genetic counselling. You can read more about this in the section below.

We know that it can be very worrying and upsetting to wonder if you or your loved ones have an increased risk of developing blood cancer. If you’d like to talk about your fears and concerns, our Support Service nurses are available to chat via phone or email. They can provide a listening ear, help you come up with questions to ask your doctor, or tell you more about genetic testing and counselling.

If genetic tests reveal that an inherited change in your genes made it more likely that you developed blood cancer, you and your family may be offered genetic counselling.

A genetic counsellor will tell you more about how gene changes are inherited, as well as the chances of a child, sibling or other family member inheriting the same gene changes or developing the same cancer. They may also tell you about reproductive options that could be available to help prevent any future children you may have from inheriting a gene change.

Lots of people in this situation find genetic counselling helpful. However, others may prefer not to know any more about hereditary gene changes or the associated risks, as this may cause additional worry or anxiety for themselves or their loved ones. It’s OK if you or your family members choose not to have genetic counselling, or if some people want to have it and others don’t.

If you do choose to have genetic counselling, you should be able to talk through everything afterwards with your hospital team. If you need more support understanding or coming to terms with anything that comes up, you can ask your doctor or clinical nurse specialist (CNS) about what help is available in your area. They may be able to provide support themselves, or refer you or your family for additional counselling or therapy.

Research has shown that there are a number of different things that can affect how likely you are to develop certain types of blood cancer.

These ‘risk factors’ include:

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

Risk factors vary between different types of blood cancer. For example, we know that myeloma only affects adults, and is much more common in men and people from an African-Caribbean background. However, many people who develop blood cancer won’t have any specific risk factors.

It is therefore important to remember that regardless of risk, all types of blood cancer are caused by changes in our genes and DNA. In practically all cases, these changes happen for reasons we can’t fully explain or are linked to things we cannot control, such as natural aging. You shouldn’t blame yourself or feel responsible for developing a blood cancer, as it’s extremely unlikely that it has been caused by anything you have done.

It's also worth knowing that radiation and chemical exposure would need to be at much higher levels than you’d experience in everyday life in the UK to pose a risk, so this won’t apply to most people.

The genetic changes in our cells that cause blood cancer are almost always outside of our control, and most changes happen for reasons that scientists and doctors may not be able to fully understand yet. It’s very unlikely that anything you do will be responsible for developing blood cancer.

However, eating well and staying active are an important part of looking after your body and mind, and can help you to feel better whether you have blood cancer or not. Keeping fit and healthy can also help you cope with, and recover from, blood cancer treatment.

Our living well section also contains information about working with blood cancer, claiming benefits and managing your money, which can help to make life easier for you if you are diagnosed with blood cancer and struggling physically or mentally.

If you or a loved one has blood cancer, it’s normal to feel anxious about your health and what a diagnosis could mean for you, your family and the future. You might also find it hard to open up about your feelings, especially if you’re trying to protect others or if you don’t know who to talk to.

However, your mental health is just as important as your physical health, and speaking up might help you feel less alone.

Whatever you’re going through, there is emotional and practical support available. Take a look at our mind and emotions page, which has more information about how you can help yourself and where to go for further support. Don’t be afraid to reach out to your doctor or GP about how you’re feeling, as they will have more suggestions about things that could help.

You may also wish to join our community forum and chat to other people in a similar situation, who understand what you’re going through.

Or, you can give us a call on 0808 2080 888 and speak to one of our nurses about your questions and worries.

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

We would like to thank Consultant Haematologists Dr Dima El-Sharkawi and Dr Victoria Grandage for checking the clinical accuracy of this information. Thank you also to Nicky Scott and Joanne Mumford from the Genetic Sciences team at Guy's & St Thomas' NHS Foundation Trust for their guidance and support.