a) Filippakopoulos et al.4 showed that JQ1, a small-molecule competitive inhibitor that blocks the interaction of bromodomains of BET proteins with acetylated lysines (Ac), can inhibit the proliferation of tumor cells expressing the BRD4–NUT oncoprotein. b) Nicodeme et al.5 showed that pretreatment of cells with another small-molecule competitive inhibitor, I-BET, which interferes with the interaction between the bromodomain of the BET protein BRD4 and Ac, can mute the transcription of genes that are induced during inflammatory responses.Reprinted by permission from Macmillan Publishers Ltd: Nature, 468:1051, 2010.