Figure 1. Restoration of tumor suppression by targeting negative regulators of PML using small-molecule inhibitors. Diagramatic presentation of the major inhibitors (yellow ovals) of PML by post-translational modifications, including phosphorylation, SUMOylation, isomerization, acetylation and ubiquitination. Specific inhibitors targeting several of these proteins (red ovals), two of which (XMD8–92 and emodin) have been shown to restore PML-induced tumor suppression. Combinations of small molecule inhibitors with genotoxic DNA damaging drugs (green oval) such as etoposide may prove to have a synergistic anticancer effect.