We showed that ubiquitin-specific protease 9X (USP9X) mediates lysine-specific demethylase 4C (KDM4C) deubiquitination, which activates transforming growth factor-β2 (TGF-β2)/Smad/ATM signaling to promote radioresistance in lung cancer (142). The gene discussed is KDM4C; the disease is lung cancer.