The expression level of gangliosides in different tissues and tumor types mainly depends on the level of expression of glycosyltransferases involved in their biosynthesis, such as the ST3 β-galactoside α2-3 sialyltransferase 5 (ST3Gal5) which is the enzyme generating monosialylated gangliosides (Fig. 1). Here, ST3GAL5 is linked to neoplasm.