NU7026 is a potent and selective inhibitor of DNA-dependent protein kinase (DNA-PK), an enzyme involved in the repair of DNA double-strand breaks through the non-homologous end joining (NHEJ) pathway. Its primary application lies in cancer research, particularly in enhancing the effectiveness of DNA-damaging treatments such as ionizing radiation and chemotherapeutic agents. By inhibiting DNA-PK, NU7026 prevents cancer cells from efficiently repairing DNA damage, leading to increased cell death and radiosensitization. It is widely used in preclinical studies to investigate DNA repair mechanisms and to develop combination therapies that exploit synthetic lethality in tumor cells. Due to its role in impairing DNA repair, NU7026 serves as a valuable tool in oncology research for identifying vulnerabilities in cancer cells, especially those with underlying defects in other DNA repair pathways.