Rpn11 is a stoichiometric subunit of the lid subcomplex of the 19S regulatory particle whereas USP14 and UCHL5 reversibly associate with the 19S, indicative of attractive and versatile roles for these molecules.22, 23, 24, 25 As a member of the ubiquitin-specific processing protease family, USP14 has been reported to be highly expressed in several kinds of carcinoma, including multiple myeloma,23 ovarian carcinoma26 and colorectal cancer.27 In this study, we have identified that USP14 promotes the cell cycle in prostate carcinoma cells by deubiquitination and stabilization of AR. This evidence concerns the gene USP14 and plasma cell myeloma.