It is noteworthy that in acute promyelocytic leukemia, the PML gene is the site of the t (15, 17) chromosomal translocation wherein it is fused to the retinoic acid receptor (RAR) gene, leading to the generation of PML-RAR fusion protein (de Thé et al., 1990; de Thé et al., 1991; Goddard et al., 1991; Kakizuka et al., 1991). This evidence concerns the gene PML and acute promyelocytic leukemia.