Used as a potent and selective inhibitor of Wee1 kinase, PD0166285 is primarily applied in cancer research to induce premature mitotic entry in tumor cells. By inhibiting Wee1, it prevents the inactivation of cyclin-dependent kinases, forcing cells with damaged DNA to enter mitosis without proper repair, leading to cell death. This mechanism enhances the effectiveness of DNA-damaging agents such as chemotherapy and radiation, making it a candidate for combination therapies in oncology. It has shown activity in preclinical models against various cancer cell lines, particularly those with p53 deficiencies, where the G1 checkpoint is compromised and cells rely more on the G2 checkpoint controlled by Wee1. Its application is mainly in experimental settings to study cell cycle regulation and to develop targeted anti-cancer treatments.