Genetic Mutations in Womb that Lead to Childhood Leukemia Found

Researchers from the U.K. have now discovered the origins of childhood leukemia by finding the first-ever mutations in the womb that lead to the condition.

Researchers found the genetic roots of childhood leukemia by "sequencing the entire 3 billion letter genome of two pairs of identical twins with leukemia". The mutations found in the study can be ideal drug targets, as they represent mutations in every single cell that has turned cancerous, researchers said.

Childhood acute lymphoblastic leukemia is the cancer of the blood and bone-marrow. In this type of cancer, cancerous cells outnumber healthy white and red blood cells, leading to infection, anemia and easy bleeding.

"It's unusual in cancer to be able to identify the mutation that kick starts the whole process. Twin children, uniquely, provide an insight into the silent beginnings of leukaemia. One implication of these new findings is that the first or 'founder' mutation might provide an appropriate target for therapy as, unlike all subsequent mutations, it is present in every cancer cell," Mel Greaves, Professor of Cell Biology at The Institute of Cancer Research, said in a news release.

The study was based on genetic samples taken from two sets of identical twins who were diagnosed with acute lymphoblastic leukemia (ALL), which is the most common type of leukemia in children. The genome analysis revealed that the gene linked with leukemia ETV6-RUNX1 that was generated in the womb was similar in both the pairs of twins. Researchers found that this mutation was the only significant mutation that linked with genetic changes that lead to the development of the cancer. The mutation occurs in one twin and is passed to the other twin via shared blood.

The study showed that there were 22 other mutations that were similar in both pairs, but none of these were significant enough for the development of leukemia.

In one of the twin pairs, researchers found that both children had inherited a mutation from their parents called NF1 that had predisposed them to neurofibromatosis, a condition that's known to be a risk factor for leukemia. Also, there were three chromosomal changes in both the twins, which might have been generated in the womb from a single source of clone cells.

The study was largely funded by Leukaemia & Lymphoma Research and conducted at The Institute of Cancer Research, London, and is published in the journal Proceedings of the National Academy of Sciences.