RARA and acute promyelocytic leukemia: Typical APL is caused by the t(15;17)(q24.1;q21.2) translocation which leads to a promyelocytic leukemia protein (PML) gene and retinoic acid receptor a (RARα) gene rearrangement on der(15)and a RARα/PML rearrangement on der(17) at the molecular level.