B4GALT2 (beta-1,4-galactosyltransferase 2) is a Golgi-localized glycosyltransferase responsible for synthesizing complex-type N-linked oligosaccharides in glycoproteins and carbohydrate moieties of glycolipids, with capacity to produce lactose 1. Beyond its canonical glycosylation function, B4GALT2 has emerged as a multifactorial disease regulator. In lung adenocarcinoma, elevated B4GALT2 expression promotes immune exclusion by depleting CD8+ T lymphocytes and creating immunologically cold tumors; B4GALT2 suppression enhances anti-PD-1 immunotherapy efficacy by increasing activated CD8+ T cell populations 2. B4GALT2 serves as a promising blood-based biomarker for hepatocellular carcinoma detection, showing superior diagnostic performance to alpha-fetoprotein in early-stage disease 3. In neuropsychiatric contexts, B4GALT2 shows differential expression in suicide-related conditions, with altered histone acetylation patterns suggesting epigenetic regulation 4. Additionally, B4GALT2 functions as an energy metabolism-related gene contributing to osteoporosis pathogenesis 5 and brain gene expression changes in chr1 pain, particularly in the dorsal anterior cingulate cortex 6. Pharmacogenetically, the B4GALT2 c.909C>T variant influences clopidogrel platelet reactivity and bleeding risk in antiplatelet therapy 78. These findings indicate B4GALT2's pleiotropic role extending beyond glycosylation to immune regulation, disease biomarking, and pharmacogenetic outcomes.