TP53 and apoptotic process: Apoptosis disorders occur by suppression, elimination, or activation of apoptotic mediators, such as CD95 and tumor necrosis factor-associated apoptosis, and of pro-apoptotic tumor suppressor genes, as well as by regulation of p53 apoptotic activity.51, 52 Moreover, mutation of the p53 tumor suppressor gene induced by UVB radiation occurs in an early stage in cutaneous tumorigenesis.8