Cancer glycan epitopes: biosynthesis, structure and function

Aberrant glycan epitopes are a classic hallmark of malignant transformation, yet their full clinical potential in cancer diagnostics and therapeutics is yet to be realized. This is partly because our understanding of how these epitopes are regulated remains poorly understood. In this review cancer glycan epitopes for the major glycan classes are summarized with a focus on their biosynthesis, structure and role in cancer progression. Their application as cancer biomarkers, in particular the more recent work on cancer glycoforms, and the advantages these offer over the glycan or protein alone are discussed. Finally, emerging concepts which expand on the current view of the cancer glycan epitope beyond the single structure, to patterns and the whole glycocalyx, are described. These new approaches that consider the cancer glycan epitope as a glycoform, or as a pattern of many epitope structures, are providing new targets both for cancer biomarkers and therapeutics currently in development at the bench and the clinic.