Our previous work demonstrated that UCHL1 could activate the p14ARF-p53 signaling pathway by deubiquitinating p53 and p14ARF as well as ubiquitinating MDM2, which might be through its two opposing enzyme activities, hydrolase and ligase, further resulting in its tumor suppressive role in NPC tumorigenesis [11], [15]. This evidence concerns the gene MDM2 and neoplasm.