USP7 and prostate cancer: The essential role of USP7 during cell cycle progression and apoptosis has been reported by other groups: i) USP7 knockdown leads to increased p53 expression and arrest of cell cycle (Cummins et al., 2004), ii) USP7 regulated various tumor-related factors expression (p53, Ki-67) in bladder cancer and prostate cancer (Song et al., 2008; Morra et al., 2019).