PSMB2 and hepatocellular carcinoma: Recently, it has been reported that loss of NUDT21 increased usage of proximal polyadenylation sites and produced shorter 3′ UTR in various oncogenes, such as PSMB2 and CXXC5, which had fewer miRNA binding sites, escaped from miRNA-mediated gene repression, and further promoted hepatocellular cancer(HCC)cell proliferation and invasion (2, 93).