TP53 and cancer: Here, we demonstrate that upon γ-irradiation, Δ133p53 promotes DNA DSB repair by promoting p73 to bind to the promoters of repair-related genes such as RAD51, RAD52 and LIG4. Additionally, we found a number of somatic mutations in the p53 REs of Δ133p53 promoter in different cancer tissues from the Catalogue of Somatic Mutations In Cancer (COSMIC) database.