What is genomics and how can it help people with blood cancer?

Your genome is like an instruction manual for your body. It holds the instructions for making and maintaining you. It’s written in a chemical code called DNA. Your genome is the whole of your DNA – all 3.2 billion letters (or ‘bases’) of it. Within your genome are approximately 20,000 genes. These are the instructions for making the proteins our bodies are built from – from the antibodies that protect us from infections, to the keratin found in our hair and fingernails.  

While genetics looks at one or a handful of genes, genomics looks at the entirety of a person’s genome. To examine a genome, all 3.2 billion bases must be read in order, in a technique known as ‘whole genome sequencing’ (WGS).

Until now, genomics has mostly been used in research, but we’re increasingly seeing it in healthcare. Genomic medicine involves the use of genomic information in a patient’s care. It represents a move away from a traditional ‘one size fits all’ approach to treatment and care to a more personalised approach. 

All cancer arises because something has gone wrong in one or more of our genes. These errors are known as mutations. Mutations may be inherited from a parent or develop through the course of our lives. Normally our body fixes these mutations but errors in important genes can mean that a cell no-longer understands its instructions and divides uncontrollably. This is how cancer develops.

By comparing the genomes of normal cells and cancer cells, researchers and doctors can get an understanding of exactly which errors have caused the cancer. This information can improve diagnosis, in turn helping doctors choose the right treatments or direct patients to appropriate clinical trials.

But people are very different. Studying a small number of genomes would not be enough to give doctors and scientists a true picture of genes and their relationship to disease. What's more, a genome by itself doesn’t tell you everything about a condition. For this, it’s essential to know more about the person who donated it, like their symptoms and physiological measurements. This is where the NHS and the 100,000 Genomes Project comes in.

The 100,000 Genomes Project was an ambitious project to sequence 100,000 whole genomes from NHS patients with rare diseases and cancers, including blood cancers. The project was designed to help patients get better diagnoses and care, enable new scientific discoveries, and to begin the process of embedding genomic medicine in the NHS. In December 2018, the project reached its goal and sequenced its 100,000th genome.  

This was a huge achievement. It also highlighted the progress scientists have made in genomics: while the first human genome took 13 years and over £2 billion to sequence, a genome can now be sequenced in several days for less than £1,000.  

Building on the success of the 100,000 Genomes Project, a new Genomic Medicine Service was established by NHS England in October 2018. The new service is expected to roll out in 2019/2020 to provide genomic tests to certain groups of patients in England.

When fully rolled-out, the service will offer genomic tests including whole genome sequencing to all children with cancer, as well as adults with sarcoma and certain types of acute leukaemia (such as acute lymphoblastic leukaemia and acute myeloid leukaemia). In time, the service will be rolled out to other cancer types such as breast and lung cancer. People with other types of blood cancer may also benefit.

If you are offered genomic testing through the NHS, your doctor will need a blood, saliva, or tumour sample, depending on your type of cancer. Your DNA will be extracted from the sample and all 3.2 billion letters of your DNA will be sequenced. This genomic information is then combined with detailed information about your health and condition. Both are then analysed together, and a report will be sent back to your hospital care team for any findings to be discussed with you.

For many people who took part in the 100,000 Genomes Project, this process took a long time – sometimes many months. For acute blood cancers, doctors need to make decisions about starting treatment quickly. Genomic tests are not yet fast enough for this purpose.  As such whole genome testing will likely be performed alongside conventional tests to begin with. However, as the Genomic Medicine Service rolls out, this process should become faster and potentially even replace some of the tests used at the moment.

Following genomic testing, some people will receive a more accurate diagnosis. This can potentially lead to more appropriate treatments or access to clinical trials. But this won’t be true for everyone. This is because we do not yet know enough about what all the differences in different people’s genomes mean. Despite this, if you consent, your collected genomic data will be held securely for further research. This will allow scientists to work together to better-understand what genetic differences are important in different diseases.

Essentially, the more genomes analysed, the better. More analyses can help to build a bigger and more detailed picture of genes involved in diseases like blood cancer, to ensure patients receive the best possible care.

Blood Cancer UK funds important research into blood cancer genomics. We also work with the Government, the NHS, and other charities to ensure that people with blood cancer receive the full benefits of genomic medicine. 

You can help shape our work – if you have received whole genome sequencing through the NHS, we would love to hear your thoughts and experiences at [email protected]

If you’d like to learn more about genomics, read NHS England’s Improving Outcomes Through Personalised Medicine report.