Most importantly, through comparing the in vivo response of the parental and USP22-Ko cancer xenografts to USP7 inhibitor P5091, we found that USP7 inhibitor treatment suppressed more growth and induced more apoptosis in USP22-Ko xenograft, which further support that targeting both USP7 and USP22 may represent a novel and effective anticancer therapeutic strategy. This evidence concerns the gene USP7 and cancer.