BRDs specifically recognize acetylated lysine residues in histone H3 and H4.137 For instance, a study has reported that IL1β or TNF-induced acetylation of H4K5Ac, H4K8Ac, and H4K12Ac mediates the recruitment of the BET proteins, BRD3 and BRD4, to the matrix degrading enzyme gene promoter, consequently upregulating their expression in human chondrosarcoma cells.138 Histone H3 acetylation, especially at H3K18Ac, facilitates the recruitment of BRD3 and BRD4 to the promoter of CXCL8 gene which encodes interleukin-8 protein. This evidence concerns the gene BRD4 and chondrosarcoma.