USP22 and hepatocellular carcinoma: To explore the impact of USP22 knockout/knockdown on the proliferative capacity of hepatocellular carcinoma cells, we employed lentiviruses expressing either USP22 single guide RNAs (sgRNAs) together with Cas9 or USP22 shRNAs to infect HepG2, Hep3B and Huh7 cells, establishing cell populations stably expressing Cas9 and USP22 sgRNA or USP22 shRNA (Figure S1B).