PFI-3 is a potent and selective inhibitor of bromodomains, particularly targeting the BRD9 and BRD7 proteins within the SWI/SNF chromatin remodeling complex. Its primary application lies in epigenetic research, where it is used to probe the biological roles of bromodomain-containing proteins in gene regulation, cell differentiation, and cancer progression. Due to its ability to disrupt protein-protein interactions involved in transcriptional activation, PFI-3 serves as a valuable tool compound in studying oncogenic signaling pathways, especially in cancers dependent on aberrant chromatin remodeling. It has been employed in cellular assays to assess anti-proliferative effects and to validate BRD9/BRD7 as therapeutic targets in leukemia, sarcoma, and other malignancies. Additionally, PFI-3 is used in combination studies with other epigenetic inhibitors to explore synergistic effects, supporting the development of novel cancer therapies. Its selectivity makes it preferred over pan-bromodomain inhibitors for more precise mechanistic studies.