FLLL32 is primarily used in research settings for its potential anti-cancer properties. It acts as a selective inhibitor of signal transducer and activator of transcription 3 (STAT3), a protein involved in cell growth and survival that is often overactive in various cancers. By inhibiting STAT3 phosphorylation and dimerization, FLLL32 helps suppress tumor cell proliferation and induce apoptosis in cancer cells. It has shown activity in preclinical studies against breast, prostate, pancreatic, and brain cancers, among others. Researchers use FLLL32 to investigate signaling pathways related to tumor progression and immune evasion. Due to its specificity for STAT3 over other STAT family proteins, it serves as a valuable tool compound in oncology and molecular biology research. FLLL32 is not used clinically and remains limited to laboratory studies. Its application is mainly in in vitro (cell culture) and in vivo (animal models) experiments to evaluate the therapeutic potential of targeting the STAT3 pathway.