New insights into the causes of childhood leukaemia

Over 30 years of research

Professor Mel Greaves from The Institute of Cancer Research conducted an analysis of more than 30 years of research – his own and from colleagues around the world – into the genetics, cell biology, immunology, epidemiology and animal modelling of childhood leukaemia. This includes a number of Children with Cancer UK funded projects Together they form the most comprehensive body of evidence ever collected on the biology of acute lymphoblastic leukaemia (ALL) – the most common type of childhood cancer, affecting more than 600 children each year in the UK. The research was published in Nature Reviews Cancer and largely funded by Blood Cancer UK and The Kay Kendall Leukaemia Fund. ALL is particularly prevalent in affluent, advanced societies and its incidence is increasing at around one per cent per year. The study found that ALL is partially caused by a genetic mutation which predisposes some youngsters to the disease. But of those children born with this genetic mutation, only one per cent go on to develop leukaemia.

A paradox of progress

A second step is also crucial in the development of the disease, which is triggered later, in childhood, by exposure to one or more common infections. Researchers found this primarily takes place in children who have experienced ‘clean’ childhoods in the first year of life, without much interaction with other infants or older children. This leads them to suggest that it might be preventable if a child’s immune system is properly ‘primed’ in the first year of life. Professor Greaves suggests childhood ALL is a paradox of progress in modern societies – with lack of microbial exposure early in life resulting in immune system malfunction. It is vital to note that this study and others into the possible causes of childhood cancer should not be seen as apportioning blame to parents of a child who has or has had leukaemia, or alarming parents of young children. It’s imperative we fund research into possible causes so we can look at reducing the number of children and young people with cancer in the future. There is much more work to be done, and there is currently nothing we know of that could have prevented a child with leukaemia from developing the disease.

Establishing whether prevention may be a possibility

We must also stress that, as Professor Greaves notes, while patterns of exposure to common infections are critical, the risk of a child developing leukaemia is also influenced by inherited genetic susceptibility, as well as chance. However, it is significant that this research indicates that we may be able to prevent most cases of childhood leukaemia – potentially sparing children the trauma and life-long consequences of chemotherapy. It’s important that this research is followed up to see if children’s immune systems can be strengthened through exposure to certain types of bacteria, and to further understand the causes of ALL. Equally it is vital that there is continued funding for research into the causes of all childhood cancers, to take forward our understanding of why children develop cancer and to establish whether prevention may be a possibility. In September Children with Cancer UK will be hosting our International Scientific and Medical Conference – Childhood Cancer 2018 – A holistic approach to Precision Medicine, this landmark conference will examine the way we understand cancer. This conference will bring together experts from around the World and will discuss the various factors that have been associated with both increased and decreased risk of childhood leukaemia and other childhood cancers (see ) http://www.childhoodcancer2018.org.uk