has role tumour antigen glucosamine oligosaccharide amino tetrasaccharide alpha-Neu5Ac-(2->3)-beta-D-Gal-(1->3)-[alpha-L-Fuc-(1->4)]-D-GlcNAc GlyGen:G81971FM CA19-9 A branched amino tetrasaccharide consisting of a sialyl residue, linked (2->3) to a galactosyl residue that in turn is linked (1->3) to a glucosaminyl residue, which is also carrying a fucosyl residue at the 4-position. (Gal)1 (GlcNAc)1 (LFuc)1 (Neu5Ac)1 Wikipedia:CA19-9 NeuAcalpha2,3Galbeta1-3[Fucalpha1-4]GlcNAc sLeA CHEBI:61793 GlyTouCan:G81971FM carbohydrate antigen 19-9 sialyl-Lewis(A) KEGG:G00257 CA19-9 antigen CHEBI:140914 WURCS=2.0/4,4,3/[a2122h-1x_1-5_2*NCC/3=O][a2112h-1b_1-5][Aad21122h-2a_2-6_5*NCC/3=O][a1221m-1a_1-5]/1-2-3-4/a3-b1_a4-d1_b3-c2 R-alpha-D-Gal-beta1,3-alpha-D-GlcNAc-(alpha1,4-Fuc)-beta1,3-D-Gal-alpha2,3-Neu5Ac 5-acetamido-3,5-dideoxy-D-glycero-alpha-D-galacto-non-2-ulopyranonosyl-(2->3)-beta-D-galactopyranosyl-(1->3)-[6-deoxy-alpha-L-galactopyranosyl-(1->4)]-2-acetamido-2-deoxy-D-glucopyranose sialyl Lewis A sialyl Lewis a antigen