Carbohydrate Markers in Colon Carcinoma

Spontaneously mutated multiple oncogenes and/or tumor suppressor genes in colon epithelial cell and its progeny, may cause proliferation out of control and create benign colon neoplasm (colon polyp). If additional mutations involve genes responsible for cell adhesion and movement, aberrant epithelial cells may become malignant (colon cancer) and invade surrounding and remote tissues, creating secondary tumors called metastases. Incidence of colorectal cancer dramatically increases at 50-65 year of age. In Europe in 2006 colorectal cancer consisted 12.9% of all cancers and caused 207,400 deaths. To laboratory detection and monitoring of colon cancer are used tumor markers. Tumor markers are substances produced by the body in response to cancer, or by cancer tissue itself. Glycoconjugate markers for colon cancer include aberrant: mucins covering the surface of the colon epithelial cells, cadherins, selectins and Ig-like adhesion molecules mediating cell-cell adhesion, integrins and integral membrane proteoglycans responsible for adhesion of colon epithelial cells to extracellular matrix, glycoconjugate components of ECM, as well as lysosomal membrane glycoproteins and exoglycosidases. Detection of colon cancer at early non malignant stage is crucial in its prevention and eradication. As colon cancer is the effect of accumulation many somatic mutations in oncogens, supressors, mismatch repair genes and many genes responsible for posttranslational modifications of proteins, multidirectional approach should be applied for its detection. A glycobiological approach to diagnosis and treatment of colorectal cancer should be directed to detection changes in glycosylation accompanying every step of colon cancer progression, and correlation between changes in glycosylation and tumor progression.