These cells can be found in the blood, the bone marrow, the lymph nodes, the spleen, and other organs. These cells multiply rapidly and replace the normal cells. Bone marrow failure occurs as malignant cells replace normal bone marrow elements. The person becomes susceptible to bleeding and infection because the normal blood cells are reduced in number.
Most cases seem to have no apparent cause.
However, radiation, some toxins such as benzene, and some chemotherapy agents are thought to contribute to the induction of leukemia . Abnormalities in chromosomes may also play a role in the development of acute leukemia. Risk factors for acute leukemia include Down syndrome , a sibling with leukemia, and exposure to radiation, chemicals, and drugs. The incidence is 6 out of 100,000 people. The WBC count is abnormal.