A new study suggests Germ-free childhoods followed by infections later in life can trigger the onset of childhood leukemia.
The study published on Monday in the journal, Nature Reviews Cancer, reviews that Acute Lymphoblastic Leukemia (ALL), the most common type of childhood cancer, is caused by a two-step process.
The first step is a genetic mutation before birth that predisposes a child to the risk of developing this form of leukemia. The second step is exposure to certain infections later in childhood, after clean early childhoods that limited exposure to infections.
The paper says more specifically, children who grew up in cleaner households during their first year and interacted less with other children are more likely to develop acute lymphoblastic leukemia.
The author, Professor Mel Greaves at the Institute of Cancer Research suggests the cancer could be preventable.
Greaves after reviewing more than 30 years of research said he had long wondered “why or how otherwise healthy children develop leukaemia and whether this cancer is preventable.”
“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.
“The research strongly suggests that (this cancer) has a clear biological cause, and is triggered by a variety of infections in predisposed children whose immune systems have not been properly primed,” Greaves said in a statement.
However, other experts warn that more specifics needs to be confirmed and emphasize that hygiene and safety are still crucial.
Population studies have found that early exposure to infection in infancy such as day care attendance and breastfeeding can protect against ALL, probably by priming the immune system, according to the study.
Greaves emphasized that infection as a cause applies only to ALL. Other types of leukemia, including infant leukemia and acute myeloid leukemia, probably have different causal mechanisms.
“Preventing childhood leukaemia would have a huge impact on the lives of children and their families in the UK and across the globe,” said Paul Workman, chief executive of the Institute of Cancer Research, London.
However, other experts are more cautiously hopeful, emphasizing that genetics and pure chance are still significant factors for developing ALL.