OGT and breast cancer: On the other hand, some glycosyltransferases, such as N-acetylgalactosaminyltransferase 4 (GalNAc-T4), GalNAc-T14, GalNAc-T6, fucosyltransferases 4 (FUT4), FUT8, and O-GlcNAc transferase (OGT) [29, 90–92], which are overexpressed in breast cancer and correlated with its prognosis, may be used as novel biomarkers or combined with traditional biomarkers to improve the sensitivity and specificity for the diagnosis of breast cancer [83, 93, 94].