RARA and acute promyelocytic leukemia: However, acute promyelocytic leukemia (APL), characterized by rearrangements of the retinoic acid receptor alpha (RARA) gene, has benefited more than any other AML subtype from targeted therapies: addition of the RARA ligand all-trans retinoic acid (atRA) to its therapy has greatly improved APL patient survival for the last few decades [15,16,17].