Acute Promyelocytic Leukemia in Childhood

Acute promyelocytic leukemia (APL) is a relatively rare form of acute myelogenous leukemia (AML). In the United States, APL in children constitutes only 5% to 10% of AML. Molecularly, the disease is characterized by a fusion protein, promyelocytic ;leukemia (PML)-retinoic acid receptor (RAR)-alpha that results from a balanced reciprocal translocation between the PML gene on chromosome 15 and the RAR-alpha (RARA) gene on chromosome 17. A major advance in the field of APL treatment has been the use of all-trans-retinoic acid (ATRA). Advances in the treatment of APL have taken this form of AML from a disease with significant morbidity and mortality to one with an excellent outcome. This has resulted largely from the incorporation of ATRA into frontline regimens with chemotherapy. Anthracyclines remain a cornerstone of treatment at this point. Recent trials have shown a role for arsenic trioxide in both newly diagnosed and relapsed APL.