RBM39 and cancer: RBM39 degraders, the anti-cancer sulfonamides indisulam (E7070), E7820, and chloroquinoxaline sulfonamide, selectively degrade RBM39 by promoting interaction of RBM39 and the adapter protein DCAF15 with the CUL4/Db1 E3 ubiquitin ligase (Han et al., 2017; Uehara et al., 2017; Du et al., 2019) (Fig. 3 B).