GCNT4 (glucosaminyl N-acetyl transferase 4) is a glycosyltransferase that mediates core 2 O-glycan branching in mucin-type biosynthesis, functioning primarily in the Golgi apparatus. The enzyme exhibits tumor suppressor activity in gastric cancer, where GCNT4 expression is significantly downregulated and correlates with poor prognosis 1. Lower GCNT4 levels are associated with increased tumor depth, nervous invasion, and advanced pathological stage, with multivariate analysis revealing GCNT4 as an independent prognostic factor for overall survival 1. Mechanistically, GCNT4 overexpression inhibits gastric cancer cell proliferation and cell cycle progression 1. The gene is regulated by multiple microRNAs including miR-485-3p and miR-1229-3p, which suppress GCNT4 expression to promote cancer progression 23. GCNT4 also modulates the TGF-β1/SMAD3 signaling pathway, with its downregulation leading to pathway activation and enhanced tumor growth 4. Beyond cancer, GCNT4 expression increases during limbal epithelial cell differentiation, particularly in abortive clones with limited clonogenic potential 5. The gene has also been identified in genome-wide studies of antipsychotic-induced metabolic effects and visceral leishmaniasis susceptibility 67.