Review Article
Roger AKroes and Joseph R M
Abstract
The oligosaccharide chains, or glycans, that decorate cell surface glycoproteins and glycolipids are among the most complex and diverse structures in vertebrate cells. It is estimated the well over half of all human proteins are glycosylated. Their expression is exquisitely regulated and is the result of the coordinated activity of distinct glycosyltransferases and glycosyl hydrolases that add or remove individual sugars to complete each glycan chain. Aberrantly expressed cell surface glycoconjugates are associated with malignant transformation, tumor progression, and metastasis and are predominantly the result of alterations in their biosynthetic machinery. They mediate key pathophysiological events during tumorigenesis including altered cellular adhesion and invasivity, molecular trafficking, receptor activation, and intracellular signal transduction in tumors.