What is the treatment for acute myeloid leukemia subtype M3?

Acute myeloid leukemia (AML) subtype M3, also known as promyelocytic leukemia, is characterized by the presence of promyelocytes with heavy granulation and often associated with specific genetic abnormalities, particularly the translocation t(15;17). This subtype is unique because it is driven by the promyelocytic leukemia-retinoic acid receptor alpha (PML-RARA) fusion gene.

The cornerstone of treatment for AML M3 is targeted therapy using all-trans retinoic acid (ATRA). ATRA works by promoting the differentiation of the abnormal promyelocytes into mature granulocytes, effectively leading to remission. When combined with chemotherapy, it has significantly improved outcomes for patients with this specific subtype of AML.

Given this mechanism of action and the specific characteristics of AML M3, the use of retinoic acid is pivotal in the therapeutic regimen for this condition. It addresses the underlying pathophysiology directly, making it the most appropriate treatment choice among the options provided. Other standard treatments for AML, such as chemotherapy alone, bone marrow transplant, or radiation therapy, do not specifically target the unique aspects of M3 and are not considered first-line treatments for this particular subtype.