Leukemia is a progressive, malignant disease of the blood-forming tissues marked by a distorted proliferation and development of leukocytes and their precursors in the blood and bone marrow.

Acute leukemia is a subtype in which the involved cell line shows little or no differentiation and usually consists of blast cells. This subtype is further differentiated into acute myelogenous leukemia (AML) and acute lymphocytic/lymphoblastic leukemia (ALL).

The incidence of AML is approximately 4:100,000. It is the more common form of acute leukemia, accounting for about 80% of diagnosed adult cases. Acute leukemia is more common in Caucasians and in males. It accounts for about 20% of cases of childhood leukemia.

ALL, the most common form of malignancy in childhood, makes up approximately 33% of all pediatric cancers. It also occurs more frequently in Caucasians. Overall, the incidence is about 30:1,000,000. For children younger than 15 years of age, the incidence of ALL in Caucasians is about 33:1,000,000, and in African Americans it is about 15:1,000,000. The disease accounts for about 80% of cases of childhood leukemia.

Acute leukemia is not fully understood but is believed to have multiple causes. Several factors have been identified as increasing the risk for developing acute leukemia, including bone marrow damage, retroviruses, and genetic disorders such as Klinefelter syndrome or Down syndrome.