ST6GAL1 and brain neoplasm: ST6Gal-I catalyzes α2,6-linked sialic acid to the terminal galactose of N-linked glycans, a modification that prevents galectin from binding to β-galactosides, a mechanism for tumor cell survival and immune evasion (190), and this enzyme is highly expressed in various cancer types including colon (194, 195), breast (196), cervical (197), leukemia (157), and brain tumors (198).