Around 100 DUBs have been identified to date, with several having pivotal roles in cancer progression; they are classified into five subcategories based on sequence similarity, four of which encompass papain-like cysteine protease DUBs [21–23], including ubiquitin C-terminal hydrolases (UCH), ubiquitin specific protease (USP), ovarian tumour (OTU) and the Josephin domain, while the Jab1/Mov34/Mpr1 Pad1 N-terminal+ (MPN+) (JAMM) sub-type belongs to the zinc-metalloprotease family. Here, COPS5 is linked to cancer.