SIRT1 and colorectal cancer: Although Lin et al. [73] reported that the USP22/SIRT1/TP53 regulatory pathway prevents DNA-damage-induced apoptosis in embryonic kidney and colorectal cancer cell lines, this observation was disputed by Armour et al. [75] who showed USP22 depletion had no effect on SIRT1 stability or TP53 acetylation status within the same cell lines.