USP7 and ovarian cancer: USP7 is frequently overexpressed in various human cancers including breast carcinomas, lung squamous cell carcinoma, lung large cell carcinoma, ovarian cancer, and chronic lymphocytic leukemia, and overexpression of USP7 protein is associated with high tumor grade, clinical aggressiveness, invasion, metastasis, and poor prognosis in cancer patients [6, 8, 10, 11].