CBP/p300-IN-3 is a p300/CBP histone acetyltransferase inhibitor. CBP/p300-IN-3 decreases MYC protein (c-MYC) levels in cells. CBP/p300-IN-3 prevents the transcription and function of c-MYC. CBP/p300-IN-3 can be used for the research of cancer and pre-cancerous syndromes[1].