Tyrphostin AG 879 is primarily used as a selective inhibitor of receptor tyrosine kinases, particularly targeting the TrkA and insulin receptor kinases. It is widely applied in research settings to study signal transduction pathways involved in cell growth, differentiation, and survival. Due to its ability to block neurotrophin signaling through TrkA inhibition, it is used in neuroscience research to investigate mechanisms underlying neuronal development and pain perception. It has also been employed in studies related to cancer biology, where it helps probe the role of tyrosine kinase activity in tumor cell proliferation and apoptosis. Researchers use AG 879 to suppress oncogenic signaling in models of neuroblastoma and other cancers dependent on tyrosine kinase activation. Additionally, AG 879 has been utilized in metabolic research for its inhibitory effect on the insulin receptor, helping to dissect insulin signaling pathways and mechanisms of insulin resistance. Its application remains mostly confined to in vitro and preclinical studies, serving as a tool compound rather than a therapeutic agent.