OGT and cancer: The elevated metabolic flux through the hexosamine biosynthetic pathway in cancer cells contributes to the increased production of uridine diphosphate N-acetylglucosamine (UDP-GlcNAc), which is the substrate of O-linked β-N-acetylglucosamine (O-GlcNAc) transferase (OGT) [24,25,26,27].