Gao et al. (2008b) demonstrated that histone deacetylase 7 (HDAC7) is required to maintain PML SUMOylation and PML NBs, but it remains unclear whether HDAC7 is an E3 ligase. Beta-catenin, a protein whose gene is highly mutated in colorectal carcinomas, has recently been shown to inhibit RanBP2-mediated SUMOylation of PML by inhibiting the interaction between RanBP2 and PML (Satow et al., 2012). The NAD-dependent deacetylase sirtuin-1 (Sirt1) also promotes PML SUMOylation independent of its deacetylase activity (Campagna et al., 2011). This evidence concerns the gene HDAC7 and colorectal carcinoma.