PD-173955 is primarily utilized in research settings as a potent and selective inhibitor of fibroblast growth factor receptor 1 (FGFR1) tyrosine kinase, with an IC50 of approximately 0.6 nM. It exhibits selectivity over other kinases and is valuable in studies investigating FGFR signaling pathways, which are implicated in various cancers, angiogenesis, and developmental biology. By inhibiting FGFR1, PD-173955 aids researchers in exploring the role of this receptor in tumor progression, metastasis, and potential therapeutic interventions. Additionally, it is employed in biochemical and cellular assays to assess kinase activity, signal transduction, and the efficacy of FGFR-targeted therapies, contributing to advancements in oncology and drug discovery.