PML and acute promyelocytic leukemia: Acute promyelocytic leukemia (APL) is a distinct subclass of acute myeloid leukemia (AML) which is characterized by a reciprocal and balanced translocation between the promyelocytic leukemia protein (PML) gene on chromosome 15 and the retinoic acid receptor α (RARα) gene on chromosome 17 [1, 2].