Glycosylation in cancer

The process of cell transformation induces profound alterations in the glycosylation pattern of the cells. Often, the carbohydrate structures formed by cancer cells resemble those expressed by the corresponding normal tissue during the fetal life (onco-developmental regulation) and are largely tissue-specific. However, some structures appear to be widely expressed by cancers of different histological origin. This is probably due to two main reasons: first, their biosynthesis is strictly controlled by the mechanisms altered in cell transformation (i.e. activation of oncogenes, inactivation of tumour-suppressor genes, altered pattern of epigenetic regulation); second, their expression provide cancer cells with a growth advantage, resulting in the selection of cells expressing a given antigen during tumour growth. In the following sections, we will first describe some of the most widely expressed cancer-related carbohydrate structures (Section 2), then we will discuss how the altered mechanisms controlling cell growth in cancer influence the glycosylation machinery (Section 3). Last, we will discuss how the cancer-related carbohydrate structures modify the cancer cell phenotype (Section 4).