Adult T-cell leukemia/lymphoma (ATL) response to arsenic/interferon therapy is triggered by PML-dependent hyper-SUMOylation by small ubiquitin-like modifier (SUMO)2/3, ubiquitination by RNF4, and proteasome-dependent degradation (Dassouki et al., 2015). Here, SUMO2 is linked to adult T-cell leukemia/lymphoma.