APL can be treated with low doses of arsenic trioxide, which induces polySUMO modification of PML and the PML-RARα fusion proteins which are then ubiquitinated by RNF4 and degraded by the proteasome (Lallemand-Breitenbach et al., 2008; Tatham et al., 2008). The gene discussed is RARA; the disease is acute promyelocytic leukemia.