Researchers aren’t clear on what causes more than 350,000 people each year to develop caner of the bone marrow, white blood cells, and immune system, known as leukemia. Ionizing radiation is a causative factor in many cases, and certain viruses appear to account for others; there is also evidence of a genetic link, meaning a susceptibility to leukemia runs in families. Some kinds of chemical exposure, such as to benzene, have been found to cause leukemia in combination with other factors.
Leukemia is among the most common cancers among children. Indeed, it is one of the few cancers to affect children in significant number at all. However, the risk of leukemia actually rises with age. Of the 3,500 cases diagnosed in the United States each year, some 90 percent are in adults. In addition to age, risk factors include myelodysplasia and other blood disorders, chemotherapy and radiation therapy for other cancers, some kinds of genetic disorder, and smoking.
Studies have shown that leukemia patients have an abnormally high number of neutrophils, which are a type of white blood cell that plays a role in the immune system. This can result from infections or burns among other causes, but it appears to be a sauce rather than an effect of leukemia—a high neutrophil count leads to chronic myeloid leukemia, the cancer doesn’t raise the neutrophil count. That means lowering the count, such as, research suggests, by reducing the intake of fatty acids called ether lipids that sustain them, can help prevent cancer.
Although leukemia is responsive to chemotherapy, a common form of treatment in severe cases involves bone marrow transplants, which replaces the diseased tissue with healthy tissue grown from donor stem cells. This procedure, however, carries with it a high risk of what is called "graft-versus-host disease," in which the transplanted cells reject the new host body, treating its cells as an infection, and cause the equivalent of an autoimmune reaction in multiple organs. This is one of the primary marrow transplants fail. A new test, that can better assess risk for graft-versus-host disease and guide doctors in preventing or treating it, may help make transplants safer, so thy can help more patients.