LYN-1604 is primarily used as a potent and selective inhibitor of LYN kinase, a member of the Src family of tyrosine kinases. It is widely applied in cancer research, particularly in studies involving B-cell malignancies such as chronic lymphocytic leukemia (CLL) and diffuse large B-cell lymphoma (DLBCL). By inhibiting LYN kinase activity, LYN-1704 disrupts downstream signaling pathways that promote tumor cell survival, proliferation, and resistance to apoptosis. The compound shows promise in overcoming resistance to BTK inhibitors like ibrutinib, making it a valuable tool in developing combination therapies. It is also used to investigate the role of LYN kinase in immune regulation and inflammatory responses. Due to its high selectivity and cellular potency, LYN-1604 serves as a critical pharmacological probe in target validation and mechanistic studies in oncology and immunology.