Acute promyelocytic leukemia (APL), a unique subtype of acute myeloid leukemia (AML), is characterized by the specific chromosomal translocation t(15;17)(q22;q21) and promyelocytic leukemia/retinoic acid receptor-α (PML/RARα) fusion protein, which is considered to be the initiating event of APL [1, 2]. The gene discussed is RARA; the disease is acute promyelocytic leukemia.