Cancer antigen 19-9, sialylated Lewis A. // Bound to available peptide oxygen. // N-acetylneuraminic acid, galactose, N-acetylglucosamine, ♥♥♥♥♥♥ and a little dash of aberrant glycosylation. // Hangs out at any mucin in town, also apolipoproteins. // Associated with cancers of the pancreas, breast, colon and lungs. // Lectins and antibody paratopes please stay away! Evading detection is a must.