Previously, researchers reported that ATF3 stabilizes “genome guardian” p53 by blocking murine double minute 2 (MDM2)-mediated ubiquitination, and a cancer-derived ATF3 mutant (R88G) devoid of ubiquitination failed to prevent p53 from MDM2-mediated degradation and thus was unable to activate DDR (7, 8). This evidence concerns the gene MDM2 and cancer.