There are two major subdivisions in adult acute leukemias, with the identification of the various forms based on the appearance of the cells and on studies of various biological and cell surface markers . Chromosome analysis often helps to identify the type of leukemia involved.
• Eighty percent of adult patients have an acute myeloid (AML) form. AML is divided into many sub-types
such as acute myelogenous or myeloblastic, acute monocytic or monoblastic (AMOL), acute myelomonocytic
(AMML), acute promyelocytic (APL) or, less commonly, erythroleukemia. With the exception of APL, there
are minimal differences in the prognosis and treatment response for each of the sub-types. Therapy is similar
for all of them. Patients with acute promyelocytic leukemia have a better response to a differentiating agent,
all-trans retinoic acid (ATRA), in combination with standard chemotherapy .
• Twenty percent of adult patients have acute lymphoblastic leukemia (ALL), which is similar to the childhood
form of leukemia. The treatment for ALL is generally different than for AML, because the lymphoblasts
respond to a larger variety of chemical agents and also because ALL occurs in a younger population.
The probability of a long-term remission is better for ALL, with one exception. People with ALL cells that
have a specific chromosome abnormality (the "Philadelphia chromosome") have a prognosis similar to
patients with AML.
Adult patients with ALL, like children with ALL, are at risk of their leukemia eventually involving the
central nervous system—the brain and spinal cord. Both treatment and prognosis are influenced by this
