CPI-169 is a potent and selective small-molecule inhibitor of the bromodomains and extra-terminal (BET) family proteins, particularly BRD4. It is primarily used in preclinical research to study epigenetic regulation of gene expression, focusing on protein-histone interactions and signaling pathways involved in cancer and inflammatory diseases. By blocking BET protein binding to acetylated histones, CPI-169 enables researchers to explore its effects on cellular processes, such as tumor cell proliferation and immune response modulation. This compound aids in identifying novel therapeutic targets and optimizing strategies for oncology treatments, including potential applications in hematological malignancies and solid tumors.