Alpha-1-Acid Glycoprotein (AGP) as a Potential Biomarker for Breast Cancer

The majority of plasma proteins are modified by the addition of oligosaccharide chains (glycans) to their surface. The process, known as glycosylation, is responsible for introducing huge structural variation and is important in the determination of functional properties expressed by the overall glycoprotein. Glycan composition and structure can vary widely, potentially showing diseasespecificity, unlike the underlying polypeptide sequence [1-3]. Therefore analysis of their structures could offer more accurate and condition-specific markers which is critical when early treatment and monitoring is crucial in tackling diseases. The monomeric units of glycans are the monosaccharides, linked together via glycosidic bonds between the –OH reducing group of C1 and any other –OH of adjacent residues (a condensation reaction). The bonds exist in either an α or β anomeric configuration, depending on the orientation of the bond, providing further opportunity to generate structural variability.