Morra etal. (2017) demonstrated the synergistic effects of combinedtreatment with USP7 inhibitors and PARP inhibitors in hormone-sensitive andcastration-resistant prostate cancer cells (Morraet al., 2017). Pharmacological inhibition of USP7downregulates the expression of CCDC6 involved in homologous recombination andresults in DNA repair defects that increase the sensitivity of PARP inhibitors(Leone et al., 2015).Our study showed the synergistic effects of P5091 and EZH2 inhibitors based on theregulation of EZH2 stabilization by USP7 in prostate cancer cells. Here, EZH2 is linked to prostate cancer.