Such an essential role of PML NB reformation in APL response and the ability of ATO to directly promote PML biogenesis (Lallemand-Breitenbach et al., 2001; Zhu et al., 1997) argues that ATO might have dual synergistic roles (PML::RARA degradation and direct enforcement of PML NB reformation). This evidence concerns the gene RARA and acute promyelocytic leukemia.