USP7 and melanoma: To investigate the role of USP7 regulated-PRC2 complex in the development of melanoma and tumor sensitivity to BRAF inhibitor in vivo, tumors developed from A375 cell lines infected with lentiviruses carrying Control shRNA, USP7 shRNA, EZH2 shRNA, USP7 shRNA and FOXO1 shRNA, or EZH2 shRNA and FOXO1 shRNA were ectopically transplanted into 6–8 weeks old athymic mice (BABL/c nude; Charles River Laboratories) (n = 10).