A review of the most comprehensive body of evidence on acute lymphoblastic leukaemia (ALL) — the most common type of childhood cancer – conducted by Professor Mel Greaves from the Institute of Cancer Research in London (ICR) indicates the disease is likely caused by genetic mutation coupled with exposure to infection.
“This body of research is a culmination of decades of work, and at last provides a credible explanation for how the major type of childhood leukaemia develops,” said Greaves.
Furthermore, “it also busts some persistent myths about the causes of leukaemia, such as the damaging but unsubstantiated claims that the disease is commonly caused by exposure to electro-magnetic waves or pollution”.
The study showed that as little as 1 percent of children born with a genetic mutation which predisposes them to leukaemia go on to develop the disease, triggered later in childhood by exposure to one or more common infections.
Crucially, most of the children with leukaemia were found to have been kept away from other infants and older children in the first year of life, thereby depriving them of the opportunity to develop a strong immune system.
According to Greaves, the incidence of childhood ALL has been growing at a rate of about 1% per year in affluent societies, which provides additional support for his findings, as wealthier households are more likely to be highly concerned about cleanliness and protecting children from all possible harms.
In addition to research on mice, population studies have found that early exposure to infection during infancy, such as day care attendance and breast feeding, can protect against ALL, suggesting that childhood ALL may be prevented though the introduction of common, yet harmless “bugs”.
The findings are truly remarkable, even without downplaying the importance of change and the likelihood that Greaves’ proposed mechanism is applicable only to ALL, but not to other types of leukaemia.
“It’s exciting to think that future childhood leukaemia could become a preventable disease as a result of this work. Preventing childhood leukaemia would have a huge impact on the lives of children and their families in the UK and across the globe,” commented Professor Paul Workman, Chief Executive of the ICR.