GALNT7 is a Golgi-resident glycosyltransferase that catalyzes O-linked oligosaccharide biosynthesis by transferring N-acetyl-D-galactosamine (GalNAc) residues to serine or threonine residues on protein substrates 1. Unlike other family members, GALNT7 predominantly acts on already glycosylated peptides to add additional GalNAc moieties, though some direct peptide transferase activity may exist. GALNT7 modifies O-glycosylation patterns of target proteins including MUC13 1, thereby influencing downstream signaling pathways such as PI3K/AKT and NF-κB 12. In disease contexts, GALNT7 is frequently upregulated across multiple cancer types—prostate 3, cervical 4, hepatocellular 1, nasopharyngeal 5, esophageal 6, and breast cancers 7—where it promotes tumor growth, invasion, and migration while facilitating immune evasion 3. GALNT7 expression is negatively regulated by miR-30d-5p and miR-214 846. Therapeutically, GALNT7 inhibition shows promise in reducing doxorubicin-induced cardiotoxicity through macrophage polarization modulation 8 and in suppressing papillary thyroid carcinoma progression 2. GALNT7 serves as an improved diagnostic biomarker for prostate cancer compared to PSA alone 3.