We concluded that SETD5 mediates OGT-dependent O-GlcNAcylation of RNA Pol II, which is involved in the gain of stemness in CRC cells because it interacts with both OGT and RNA Pol II, the OGT-catalyzed glycosylation of RNA Pol II is dependent on SETD5. Here, OGT is linked to colorectal carcinoma.