UBE2E2 and hepatocellular carcinoma: Ubiquitin conjugating enzyme E2S (UBE2S), a well-established k11 linkage-specific E2 corresponding to a 24 kDa peptide [2], was reported to produce aberrantly higher expression and poor outcomes in multiple human cancers such as colorectal cancer (CRC), glioma, and hepatocellular carcinoma (HCC) [2–4].