[Retinoic acid receptor alpha gene in t (15; 17) APL]

A t(15; 17) (q22; q21) translocation is identified in most patients with acute promyelocytic leukemia (APL). This translocation constructs fusion genes between retinoic acid receptor alpha (RARA) at 17q21 and PML at 15q22. These rearrangements can be detected in the majority of patients with APL but not in other types of leukemias, by Southern blotting. Breakpoints cluster in limited regions of RARA and PML, and PML/RARA and RARA/PML transcripts can also be detected by RT-PCR. Although PML/RARA and RARA/PML fusion products are transcribed in APL, PML/RARA may play an important role in the etiology of APL. Clinically, most APL patients achieve remission by oral administration of high dose all-trans retinoic acid.