PML and acute promyelocytic leukemia: Acute promyelocytic leukemia (APL), approximately 5–10% of childhood acute myeloid leukemia (AML) cases, is characterized by a chromosome translocation t(15; 17), which produced the promyelocytic leukemia protein-retinoic acid receptor α (PML-RARα) fusion gene, resulting in the production of PML-RARα oncoprotein [1].