What Causes Childhood Leukemia?

The exact underlying cause of childhood leukemia is not known. A majority of children with leukemias do not have identified risk factors that are found in adults.

Still, scientists and doctors have learned that specific changes in the DNA can cause bone marrow cells to grow out of control and convert into leukemia cells. DNA is the chemical component found in all body cells that makes up our genome – a collection of genes that control how cells function. Humans usually look like their parents because they inherit the same DNA.

Some genes control and regulate when body cells grow, divide, and die at the right time. Oncogenes are the set of genes involved in the growth and division of the cells. While tumor suppressor genes are the ones that cause and control the rate at which cells die.

Cancers usually develop when there is a mutation in the DNA (or other types of changes) that turn off tumor suppressor genes or keep oncogenes turned on. These changes in the genetic makeup can be inherited from parents (e.g., in most cases of childhood leukemias), or they might happen randomly during an individual’s lifetime.

Chromosome translocation is one of the most prevalent types of DNA change that can lead to leukemia in children. Human DNA is composed of 23 pairs of chromosomes. In this translocation, DNA of one or more genes breaks off and becomes attached to a different chromosome. For example, this type of translocation is seen in nearly all cases of childhood leukemia, especially of myeloid type. More specifically, lymphocytic leukemia (ALL) is a type of leukemia in which swap of DNA occurs between chromosomes 9 and 22 – and this translocation leads to the Philadelphia chromosome. Philadelphia chromosomes are responsible for creating an oncogene known as BCR-ABL, which alters the way how leukemia cells grow and divide.