For example, it was reported that SUMOylation of PML facilitates the assembly of the PML-NBs promoting tumor suppressive responses and that SUMOylation of PML-RARA is essential for its leukemogenic activities (Zhong et al., 2000b; Zhu et al., 2005; Shen et al., 2006), however other reports indicated that, in cells exposed to ATO, SUMOylation of PML and PML-RARA promote their ubiquitin-mediated degradation (Lallemand-Breitenbach et al., 2008; Tatham et al., 2008). This evidence concerns the gene PML and neoplasm.