USP22 and hepatocellular carcinoma: Furthermore, the inhibited cell viability and the increased lipid ROS induced by USP22 knockout/knockdown in the presence of Sorafenib can be rescued by the inhibitor of ferroptosis, Ferrostatin‐1 (Fer‐1) and 1,8‐Diazafluoren‐9‐one (DFO) (Figure 5F,G), further demonstrating that USP22 inhibition promotes Sorafenib‐induced ferroptosis in hepatocellular carcinoma cells.