PML and acute promyelocytic leukemia: More than 95% APL results from the specific chromosomal translocation t (15; 17) (q22; q12~21) so that the promyelocytic leukemia (PML) gene on the 15th chromosome and the retinoic acid receptor α (RARα) gene on the 17th chromosome fuse together to form the PML/RARα fusion gene, which is a marker of APL in the early diagnosis and prognostic monitoring [30].