USP20 and hepatocellular carcinoma: In hepatocellular carcinoma, DNA damage-induced ATR kinase activation phosphorylates and stabilizes USP20, which subsequently stabilizes SLC7A11 by exercising its deubiquitinating enzyme activity to disassemble K48-linked polyubiquitination at lysine residues K30/K37, thereby counteracting its proteasomal targeting [46].