Can we prevent childhood leukaemia?

Professor Sir Mel Greaves’ research makes the perfect short and snappy headline. His research paper entitled ‘Can we prevent childhood leukaemia?’ was published in 2021 in Leukaemia, one of the most influential scientific journals for cancer in the world. 

Leukaemia is the most common childhood cancer and, through many years of dedicated work and research, a large proportion of children can now be successfully treated. Even with huge advancements in treatments, I think we would all agree that not having leukaemia in the first place is better. Talking about why he started researching childhood leukaemia, Mel said:

Connecting the dots

Mel believes the key to preventing childhood leukaemia is infection. There are many microbes in our environment that can infect us ranging from the common cold to viruses like pneumonia. We normally look at infections as things to be avoided, but this isn’t always the case. Some viruses can make us immune to other bacterial diseases, and there are ‘good’ bacteria that help digest food as part of the gut microbiome (the collection of bacteria, fungi and other microbes that live in your stomach and intestines).

That doesn’t make it less odd that scientists believe that what triggers leukaemia is a lack of exposure to infections early in life. Mel’s team discovered that ALL starts before birth, in the womb, when a blood cell acquires a genetic mutation. These mutated cells persist for some years after birth but only develop into ALL if they acquire a second mutation. This second mutation can be triggered by an overreaction to infection. Data suggests that this overreaction can happen when a child hasn’t been exposed to many bacteria and viruses early on, because the child’s immune system hasn’t practiced enough to ‘know’ what a sensible reaction would be.

So, how can we prevent it? Mel and his team at the Institute of Cancer Research think that introducing children to harmless bacteria early in life could protect them from developing acute lymphoblastic leukaemia (ALL).

Not like other cancers

Mel said scientists have known for a long time that infections are part of the cause of a lot of all cancers worldwide. However, increased numbers of infections normally mean increased amounts of cancer. For ALL, this didn’t seem to be the case. Looking at factors which are closely linked to the number of infections a child is exposed to, Mel found evidence to support the idea that less opportunity for exposure to infections was associated with higher risk of ALL.

The research, undertaken by scientists in the UK and USA, showed that at-risk children who had spent more time in day care, had older siblings, and were breastfed were less likely to develop acute lymphoblastic leukaemia, whilst children born via caesarean were more at risk. These factors are called ‘social risk variables’.

Mel said: 

Working with CCLG

In 2019, Mel applied for funding from CCLG to test his hypothesis. This sparked a years’ research into developing model systems of leukaemia and how it interacts with the immune system. By the end of the project, the team had found strong evidence to show that common infections could trigger the development of ALL.

This project was the first step in what would be a long journey, translating the idea of infection and leukaemia being linked into a way of preventing leukaemia in children. CCLG’s funding has given the team enough data to secure a research grant from Cancer Research UK, where they will investigate whether introducing friendly bacteria early on could prevent at-risk children from developing B-cell acute lymphoblastic leukaemia.

Another success of this project is that it provided training for an early career researcher, Dr Valeria Cazzaniga, who then went on to take a senior position in a leading cancer charity. Keeping young researchers in the childhood cancer research world is very important, in Mel’s opinion, because “ambitious and challenging research takes a very long time. It absolutely requires a pipeline of excellent young scientists, who can be mentored and encouraged, to keep the show on the road.”

You can also read more about Mel's work in his own words.