KAT5 and neoplasm: USP7 has recently been found to promote tumor evasion of the immune system by deubiquitinating and stabilizing its substrates, e.g., Foxp3 (Forkhead box P3) and Tip60 (Tat-interactive protein-60 kDa) that play critical roles in enhancing the immunosuppressive functions of regulatory T cells (Treg) and suppressing tumoricidal effector T cells (Teff) (van Loosdregt et al., 2013; Wang et al., 2016a, 2017a).