Sialic Acid and Cancer 174 Sylvain Julien and Philippe Delannoy Contents Introduction ..................................................................................... 1420 Expression of N-Glycolylneuraminic Acid in Cancers ....................................... 1420 α2,6-Sialylation of N-Acetyllactosamine ...................................................... 1420 Sialyl-Tn Antigen .............................................................................. 1421 Sialyl-Lewis x (sLe x ) ............................................................................ 1421 Gangliosides .................................................................................... 1422 Anticancer Vaccine Strategies Targeting Sialylated Antigens ............................... 1423 Concluding Remarks ........................................................................... 1424 References ...................................................................................... 1424 Abstract Sialic acids are nine-carbon acidic monosaccharides found in terminal position of glycan chains. The sialylation of cell surface glycoconjugates is frequently altered in cancers, resulting in the expression of sialylated tumor-associated carbohydrate antigens that are specific markers for this disease. Because sialylated glycans are involved in many biological processes, their expression by tumor cells is often associated with increased aggressiveness and metastatic potential of the tumors. The sialylated tumor-associated carbohydrate antigens are usually weakly expressed by healthy tissues and can be therefore used as immunotherapeutic targets for anticancer vaccines. This chapter summarizes the main tumor-associated sialylated structures and their role in cancer cells biology as well as their use for the development of anticancer vaccines. S. Julien (*) • P. Delannoy Structural and Functional Glycobiology Unit, University of Sciences and Technologies of Lille, Villeneuve d’Ascq, France e-mail: sylvain.julien@univ-lille1.fr; philippe.delannoy@univ-lille1.fr # Springer Japan 2015 N. Taniguchi et al. (eds.), Glycoscience: Biology and Medicine, DOI 10.1007/978-4-431-54841-6_193 1419