OGT regulates nutrient sensing and multiple signaling pathways though its reversible posttranslational modification of proteins by the addition of the O-GlcNAc moiety and is now being appreciated as a possible regulatory switch, influencing protein-protein interactions, glucose metabolism, proteasome function, the transcriptional machinery, and mechanisms of cellular invasion and proliferation in breast cancer in cancer biology [24]–[27], [32]. This evidence concerns the gene OGT and breast carcinoma.