Leukemia is caused by an overproduction of blood cells that do not die off normally, taking up space needed for healthy blood cells. It is not a communicable disease and anyone can develop leukemia. Symptoms of leukemia can include fever, fatigue, bruising, and bone or joint pain. A blood test and sometimes tissue test can confirm a diagnosis of leukemia, which can be either acute or chronic. Treatment involves chemotherapy, radiation, and sometimes bone marrow transplants, though regular exercise may help reduce cancer risks. Leukemia remains a serious disease.