PML and acute promyelocytic leukemia: Arsenic trioxide, for instance, promotes SUMO1/2 chain formation on PML-RARα, inducing its degradation and differentiation of promyelocytic leukemia cells, and is now a standard therapy for acute promyelocytic leukemia (APL) (Yang et al., 2018; Cervia et al., 2023; Rabellino et al., 2012).