Bromodomain-containing protein 4 (BRD4) is a member of the BET class chromatin reader proteins that bind acetylated histones and play a key role in transcriptional regulation and transmission of epigenetic memory. Remains associated with acetylated chromatin throughout the entire cell cycle and provides epigenetic memory for postmitotic G1 gene transcription by preserving acetylated chromatin status and maintaining high-order chromatin structure. BRD bromodomains serve as recognition motifs for acetylated lysine residues on histones, while the NET domain may function by promoting phosphorylation of the C-terminal domain (CTD) of RNA Polymerase II. Some specific inhibitors of BRD4 that prevent binding to acetylated histones by binding Asn-140 and Asn-433 are promising therapeutic molecules for the treatment of leukemias. BRD4 is a potential therapeutic target in many diseases including breast cancer, AML, multiple myeloma, colon cancer and others.