New evidence of infection link to childhood Leukaemia

Every 20 minutes someone in the UK is diagnosed with cancers of the blood such as leukaemia, lymphoma and myeloma. UK researchers have for the first time identified the molecule that stimulates leukaemia to develop in children, according to a study published in the April edition of the Journal of Clinical Investigation.

Scientists at The Institute of Cancer Research have observed that pre-leukaemic stem cells multiplied substantially at the expense of normal cells when exposed to a molecule produced in the body called TGF.

TGF is triggered as a normal response by the body to infection and so the new finding provides the first experimental evidence as to how common infections might trigger childhood leukaemia.

“We had already identified that a genetic mutation occurring in the womb created these pre-leukaemic cells,” Dr Anthony Ford from The Institute of Cancer Research (ICR) says. “But we have been looking for a trigger that could send these cells down the pathway to leukaemia. We believe TGF is part of that missing link.”

In a study of identical twin girls last year, ICR scientists discovered a genetic mutation – the fusion of the TEL (ETV6) and AML1 (RUNX1) genes – was responsible for initiating childhood acute lymphoblastic leukaemia in the womb.

This mutation means pre-leukaemic cells grow in the bone marrow as a silent time bomb that can stay in the body for up to 15 years, but requires other factors to convert into leukaemia. Evidence suggests the mutation may be present in as many as one in 100 babies,but only about one in 100 of those children with the mutation then go on to develop leukaemia.

The latest ICR study, funded by Leukaemia Research, found TGF creates conditions that allow the pre-leukaemic cells to multiply. This increases the chance that some will become even further damaged in a way that results in the child developing leukaemia. Before this study, there had been only circumstantial evidence to implicate infections in the progression from a child carrying pre-leukaemic cells to actually having leukaemia. There was no evidence of the mechanism by which this might happen. While infection is clearly only one factor in triggering progression, this study greatly increases the strength of evidence for its role in the commonest form of childhood leukaemia.

It also gives hope for the development of more effective early diagnosis and treatment for childhood leukaemia.

Article by AnnA