A hallmark in acute promyeloid leukemia (APL) is a chromosomal translocation that fuses the promyelocytic leukemia gene (PML) on chromosome 15 and the retinoic acid receptor alpha gene (RARα) on chromosome 17 into a fusion gene PML-RARα [3, 4]. The gene discussed is RARA; the disease is acute promyelocytic leukemia.