ST3GAL6 (ST3 beta-galactoside alpha-2,3-sialyltransferase 6) is a Golgi-resident sialyltransferase that catalyzes the transfer of sialyl residues from CMP-N-acetyl-beta-neuraminate to terminal galactose residues on type II glycan chains (Galβ1-4GlcNAc) of glycoproteins and glycolipids 12. This enzymatic activity generates sialyl-Lewis X epitopes that function as critical selectin ligands for neutrophil recruitment and lymphocyte homing 3. ST3GAL6 plays a context-dependent role in cancer biology. In colorectal cancer, reduced ST3GAL6 expression promotes tumor progression through PI3K/Akt pathway activation, while lncRNA ST3Gal6-AS1 positively regulates ST3GAL6 to suppress cancer cell proliferation and metastasis 4. Conversely, elevated ST3GAL6 expression in urinary bladder cancer correlates with poor prognosis and increased cell invasion 5. In multiple myeloma, high ST3GAL6 expression enhances bone marrow homing and stromal cell adhesion through α2,3-sialylation, associating with inferior survival 6. ST3GAL6 expression is also dysregulated in hepatocellular carcinoma, with diminished expression levels 7, and maternal ST3GAL6 genetic variants influence human milk oligosaccharide composition 8. Among the three α2,3-sialyltransferases, ST3GAL6 specifically modifies EGFR and influences cell proliferation and morphology distinctly from ST3GAL3 and ST3GAL4 9.