Arsenic trioxide (ATO) plus all-trans retinoic acid (ATRA) had been proved a successful strategy in acute promyelocytic leukemia (APL), a unique AML subtype characterized by the fusion protein of promyelocytic leukemia (PML)–retinoic acid receptor ɑ (RARɑ). This evidence concerns the gene PML and acute promyelocytic leukemia.