CREB-binding protein, also known as CREBBP or CBP or KAT3A, is a coactivator encoded by the CREBBP gene in humans. CBP has intrinsic acetyltransferase functions; it is able to add acetyl groups to both transcription factors as well as histone lysines, the latter of which has been shown to alter chromatin structure making genes more accessible for transcription. CBP alone has been implicated in a wide variety of pathophysiologies including colorectal cancer as well as head and neck squamous cell carcinoma. In these diseases, association of CBP with β-catenin has been shown to promote cancer cell proliferation and disease aggressiveness, whereas p300/ β-catenin leads to cell differentiation and/ or apoptosis. CBP has also been shown to help modulate liver function via maintenance of energy homeostasis in response to changes in cell nutrition conditions by regulating the activity of transcription factors and genes responsible for lipogenesis and gluconeogenesis. CBP is also implicated in the etiologies of several other diseases including hematologic malignancies and other solid tumors, diabetes, schizophrenia, Alzheimer's disease, depression, and many other neurological conditions.