“…It can stimulate the proteolytic activity of 20S proteasome and enable protein/peptide substrates to diffuse into the environment of proteasomes [4,5]. REGc has been reported to be highly expressed in human breast cancers [6,7], thyroid cancers [8], hepatocellular carcinomas [9] and colorectal cancers [10]. In addition, recent studies have showed that REGc play a role in protein degradation of tumor suppressor p53 [11,12], oncogene steroid receptor coactivator-3 (SRC-3) [13], as well as cell cycle regulator proteins including p21, p16 and p19 [14].…”