Acute Leukemia Maram Haddad Acute Leukemia Maram Haddad Leukemia is a disease characterized by neoplastic proliferation of one of the blood-forming cells. The different types of leukemia are classified according to the cell type involved and as acute or chronic, depending on the state of maturity of the neoplastic cells and the expected duration of the disease. The average survival of untreated patients with acute leukemia is about three months, but the course of the disease may vary considerably. It is important to distinguish between the two major types because the response to chemotherapy is much more favorable in ALL than in AML and different drugs are ordinarily used for inducing remission.
Acute leukemia accounts for nearly half of all neoplasms in children.
Patients with Down's syndrome or mongolism, a defect characterized by trisomy of chromosome 21, have approximately a twentyfold higher incidence of acute leukemia than normal. Both ALL and AML occur, and the type of leukemia appears to be related to that usually expected at the age of occurrence. A number of other congenital conditions are also associated with an increased incidence of leukemia, although the risk is less than in Down's syndrome. Although there is no common specific chromosomal lesion, most of these syndromes are characterized either by chromosomal aneuploidy or by a tendency to chromosomal breakage. Chromosome analysis of dividing leukemic cells in the marrow shows one or more karyotypic abnormalties in nearly half of patients with acute leukemia.