The American Cancer Society reports that leukemia is the most common cancer in children and adolescents, affecting roughly 3,500 children in 2009. The Leukemia and Lymphoma Society reports that many of these childhood cancers have a survival rate as high as 90 percent. It is often hard to understand why certain children develop leukemia while others do not. Risk factors have been identified that may increase the likelihood of a leukemia diagnosis in certain children.
Inherited Syndromes
Many inherited syndromes can predispose a child to leukemia. Li-Fraumeni syndrome, a rare condition that affects the p53 suppressor gene, may make a child more susceptible to certain types of cancer, such as leukemia and bone cancers. According to the American Cancer Society, a diagnosis of Down syndrome, a genetic condition that causes mental retardation and genetic delays, increases the likelihood of a child contracting leukemia by 10 to 20 percent. Down syndrome babies can also be affected by a condition known as transient leukemia in the first month of their lives. Transient leukemia has leukemia-like characteristics that disappear over time, often without any treatment or intervention. Klinefelter syndrome, a genetic condition affecting males born with an extra X chromosome, causes infertility and an increased risk for childhood-onset leukemia.
Environmental Exposure
The risk of developing leukemia can increase as a result of certain environmental factors. Children exposed to high levels of radiation, such as Japanese atomic bomb survivors, have an increased risk of leukemia. Children exposed to X-rays during early fetal development may also experience an increased risk, although to a lesser extent. Children who have been treated with chemotherapy agents, such as alkylating agents and epipodophyllotoxins, have been shown to be at an increased risk of cancer later in life. Many believe that exposure to pesticides or electromagnetic fields increases the likelihood for childhood leukemia, but the American Cancer Society has found no strong evidence linking cancer to either factor.
Immune Suppression
Children who take medications that suppress the immune system are more likely to develop leukemia. These drugs, also known as immunosuppressants, work to suppress the body's natural response to fight what it perceives as a foreign invader. Children who have conditions in which the body has an inappropriate immune response, such as lupus, HIV or rheumatoid arthritis, receive these medications to help prevent the body from attacking itself. People who have received organ transplants also take immunosuppressants to keep the body from rejecting the new organ. While immune system suppressants have many benefits, they may also prevent the body from mounting a defense against cancer cells, increasing the risk of leukemia and other cancers.
Siblings and Leukemia
Children who have brothers or sisters with leukemia are two to four times more likely to get leukemia than those without. The American Cancer Society reports that in identical twins, however, the risk of developing leukemia jumps to 20 percent. If leukemia occurs within the first year of life in an identical twin, the risk to the other twin is greater still. Many physicians believe that this increased risk is related to the twins sharing leukemia cells while in the womb.
