Acute promyelocytic leukemia (APL) is a subtype of acute myeloid leukemia (AML) that is characterized by the overproduction of promyelocytes, which are immature white blood cells. APL cells have a specific abnormality that involves chromosomes 15 and 17, leading to the formation of an abnormal fusion gene called PML/RARĪ±, which causes many of the features of the disease. APL accounts for about 10-15 percent of all adult AML cases diagnosed each year.
Symptoms of APL result from the overproduction of promyelocytes and the underproduction of healthy blood cells. They include fevers, fatigue, loss of appetite, frequent infections, and bleeding or bruising easily. APL is an aggressive form of AML that develops quickly and needs treatment straight away.
Treatment for APL differs from treatment for other AML subtypes. Because of advances in diagnosis and treatment of this disease, APL is now considered the most curable form of adult leukemia, with cure rates of 90 percent reported from centers specializing in APL treatment. Treatment for APL usually involves a combination of two drugs: all-trans-retinoic acid (ATRA) and arsenic trioxide, or ATRA with chemotherapy. The initial remission rate of APL patients treated with ATRA and an anthracycline, such as idarubicin, is about 90 percent.
In summary, APL is a subtype of AML that is characterized by the overproduction of promyelocytes, leading to a shortage of healthy blood cells and a range of symptoms. It is an aggressive form of leukemia that requires prompt treatment, but it is also considered the most curable form of adult leukemia.
