ZUP1 and neoplasm: They are classified into seven families based on their sequence and structural similarity, including the Ubiquitin-specific proteases (USPs), Ovarian tumor proteases (OTUs), Josephins and JAB1/MPN/Mov34 metalloenzymes (JAMMs), Machado-Josephin disease proteins (MJDs), Ubiquitin carboxyl-terminal hydrolases (UCHs), motif interacting with ubiquitin-containing novel DUB family proteases (MINDYs) and zinc finger-containing ubiquitin peptidase 1 (ZUP1) (6, 7) (Figure 2).