Biology of colon cancer: an overview

Abstract

The altered growth characteristics of neoplastic cells have recently been associated with changes in membrane glycoproteins present on the cell surface. Since the carbohydrate moieties of surface membrane glycoproteins are asymmetrically located on the external cell surface, these glycoconjugates are likely candidates for providing cell surfaces with many of their biological properties. Using specific external cell surface labeling techniques, we have broadened our investigation of tumor cell surface glycoconjugates to include studies on cultured human epithelial cells from fetal intestine and from colonic carcinoma. We have isolated by affinity chromatography and gel filtration and integral membrane glycoprotein, termed Galactoprotein I, from a cultured human colonic adenocarcinoma cell line, which appears to be identical in many respects to CEA. Further examination of cell surface glycoproteins regarding quantitative and qualitative alterations and topographical redistribution should provide an insight into the biological aspects of tumor development.