A risk factor [2] is anything that increases a person's chance of developing cancer. Although risk factors often influence the development of leukemia, most do not directly cause leukemia. Some people with several risk factors never develop leukemia, while others with no known risk factors do. However, knowing your risk factors and talking about them with your doctor may help you make more informed lifestyle and health care choices.

Leukemia can be caused by a genetic mutation that is inherited (passed from generation to generation within a family) or develops during a person's life because of environmental factors, smoking, and chemical or radiation exposure. However, no specific cause can be found for most patients with leukemia.