The underlying mechanism of RANBP2′s action, involving the SUMOylation and subsequent downregulation of CCAAT/enhancer-binding protein alpha (CEBPα) by RANBP2, accounts for OGA transcriptional inhibition, which causes hyper-O-GlcNAcylation and promotes HCC progression. The gene discussed is RANBP2; the disease is hepatocellular carcinoma.