22 May 2018 - 11:31
New study reveals missing microbes 'cause' childhood cancer
London: A major new analysis reveals for the first time the likely cause of most cases of childhood leukemia, following more than a century of controversy about its origins.
Professor Mel Greaves from The Institute of Cancer Research, London, assessed the most comprehensive body of evidence ever collected on acute lymphoblastic leukemia (ALL), the most common type of childhood cancer.
ALL affects one in 2,000 children, and its rate has been increasing in affluent countries by about 1 percent a year. Even though scientists already knew there were some genetic risk factors, this research gives a solid basis to how the devastating cancer forms.
His research concludes that the disease is caused through a two-step process of genetic mutation and exposure to infection that means it may be preventable with treatments to stimulate or 'prime' the immune system in infancy.
The first step involves a genetic mutation that occurs before birth in the fetus and predisposes children to leukemia, but only 1% of children born with this genetic change go on to develop the disease.
The second step is also crucial. The disease is triggered later, in childhood, by exposure to one or more common infections, but primarily in children who experienced 'clean' childhoods in the first year of life, without much interaction with other infants or older children.
"The research strongly suggests that ALL has a clear biological cause, and is triggered by a variety of infections in predisposed children whose immune systems have not been properly primed," said Greaves.
We urge parents not to be alarmed by this study, childhood leukaemia is very rare and only around one in 2,000 children will develop it," explains Alasdair Rankin, from the UK blood cancer charity Bloodwise.
"While developing a strong immune system early in life may slightly further reduce risk, there is nothing that can be currently done to definitively prevent childhood leukaemia.
"As noted by this study, other factors influence its development, including pure chance."
Prof Charles Swanton FRS, Cancer Research UK's chief clinician, said "This research sheds light on how a form of childhood blood cancer might develop, implicating a complex combination of genetics and early exposure to germs, dirt, and illness. But its important to emphasise that less than one per cent of children who have the genetic predisposition described in this review, go on to develop acute lymphoblastic leukaemia (ALL).
Childhood leukaemia is rare and it's currently not known what or if there is anything that can be done to prevent it by either medical professionals or parents. We want to assure any parents of a child who has or has had leukaemia, that theres nothing that we know of that could have been done to prevent their illness."