Leukemia Affecting Children

Why is it that some forms of Leukemia affect mostly children? Nicoletta Lanese is a staff writer for Live who recently composed an article giving more information on the subject. The leukemias that seem to target children may exploit specific vulnerabilities that are found only in immature cells.

These forms of leukemia tend to begin early in life and affect far more children than adults. This type of cancer disrupts normal cell growth in the blood and bone marrow. This accounts for almost 1/3 of all childhood cancer cases, as reported to the American Cancer Society. It usually progresses quickly and requires immediate and aggressive treatment.

Leukemia of adults and children do not share the same genetic roots, according to Dr. Thomas Mercher, director of hematology-oncology research for the French National Institute of Health and Medical Research and the Gustave Roussy research institute in Villejuif, France. The specific genetic quirks seen in childhood leukemia cells may arise very early in life or in the womb, but according to studies how this happens is generally unclear. New research hints that childhood leukemia may be able to hijack only the young, developing cells and not the adult mature cells.

Mercer and colleagues gathered genetic samples from young patients with a particularly aggressive form of acute myeloid leukemia and replicated the disease in their mouse models. This study was published in the journal Cancer Discovery which hints at why cancer appears early in life and in children, often before 2 years of age.

When the team activated ET02-GLIS2 in fetal stem cells, the resulting proteins seemed to tamper with cellular pathways that normally turn the cells into healthy blood cells. The fusion gene flipped a molecular switch that transformed the stem cells into aggressive leukemia. Blocking this activation in the same fetal mice flipped the switch back and curbed the cancer growth to allow stem cells to turn into normal blood again.

The adult stem cells appeared to be much less prone to rise to leukemia when ETO2-GLIS2 was activated and the fusion gene did not appear to be a key driver of the progression of leukemia in adult mice.

Mercer said that the developmental stage of the cells in which the mutation arises determines the aggressiveness and type of leukemia that a person gets. This shows that more people should be paying attention to the fetal bone marrow environment where the hematopoietic stem cells can be found, according to Dr. Mignon Loh, a pediatric hematologist-oncologist at the University of California, San Francisco, who was not part of the study.

This may also shed some light on how other forms of childhood leukemia rely on fusion genes. Further research into the nature of fetal stem cells, in general, could reveal other avenues by which leukemia exploits developing cells. Drugs could be developed to stall or stop the disease by pinpointing how child-specific mutations cause leukemia, and just how wonderful would that be?

Dr Fredda Branyon