PD 158780 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 it to investigate the mechanisms of cancer development and progression, as EGFR is often overactive in many types of tumors. Additionally, PD 158780 is used to explore potential therapeutic strategies targeting EGFR in cancer treatment. Its ability to inhibit EGFR activity makes it a valuable tool in preclinical studies aimed at understanding and developing targeted therapies for EGFR-driven cancers.