Biomarker can be defined as "a characteristic that is objectively measured and evaluated as an indicator of normal biological processes, pathogenic processes, or pharmacologic responses to a therapeutic intervention". (1) The term biomarker can be divided into four groups: a diagnostic biomarker, i.e. an indicator able to distinguish between a healthy population and patients with a particular disease; a prognostic biomarker provides information about the patient’s outcome (i.e. development of an aggressive form of a disease); a predictive biomarker affords prediction of the response of the patient to treatment or therapy, a therapeutic biomarker is a biomolecule which could be used as a target for the therapy.(2)
Glycans are compounds consisting of a large number of monosaccharides linked via glycosidic bonds and present on proteins (glycoproteins) or lipids (glycolipids). Glycans provide much higher number of combinations and variations compared to proteins or DNA since monosaccharide chains can be linear and also branched, can be bound either by α or β linkage or can be linked to a polypeptide chain via oxygen (O-linked) or nitrogen atom (N-linked).(2) Furthermore, every single cell in our body is covered by a dense layer of glycans and 70-80% of all our proteins are glycosylated. Glycans are involved in numerous physiological and pathological processes.
Glycans as cancer biomarkers
As cancer is the leading cause of death worldwide and new ways of treatment are still being developed, there is a growing need for an early and reliable diagnosis of this disease.
Extensive research is focused on the role of glycans and changed glycosylation in tumorigenesis and to study changes in glycan structures in glycoprotein biomarkers. In our company we aim to identify glycan-based biomarkers applicable in cancer management since cancer cells produce typical glycan changes, which are different from glycans produced by healthy cells. Thus, we validate glycan-based biomarkers for early cancer diagnostics, cancer staging and therapy monitoring.