Tyrphostin AG528 is primarily used in research settings as a selective inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase. It is employed to study the role of EGFR signaling in various cellular processes, including cell proliferation, differentiation, and survival. Researchers utilize Tyrphostin AG528 to investigate its potential effects on cancer cells, as EGFR is often overexpressed in many types of tumors. By inhibiting EGFR activity, it helps in understanding the mechanisms of tumor growth and the development of targeted cancer therapies. Additionally, it is used in biochemical assays to explore the downstream signaling pathways influenced by EGFR inhibition.