ABSTRACT
The CEA Gene Family The carcinoembryonic antigen (CEA) gene family consists of 29 genes which are located
within on the long arm of chromosome 19. CEA was first described in 1965.1,2 The isolation of cDNAs or genes for CEA family members led to their identification in 1986 as members of the immunoglobulin (Ig) supergene family.3"9 All CEA family members are glycoproteins com posed of an N-terminal Ig variable region-like domain, followed by 0,2,3,4, or 6 Ig constant region-like domains of subtype A or B, and terminated by a processed hydrophobic C-terminal domain. The CEA family may be subdivided into two groups based on sequence comparisons. The first is CEA and the CEA cross-reacting molecules, including nonspecific cross-reacting antigen (NCA), biliary glycoprotein (BGP) and CGM-6; the second consists of the pregnancyspecific glycoproteins. The CEA subgroup is subdivided further by structural characteristics into those members attached to the outer cell membrane by glycophosphatidyl inositol (CEA, NCA, CGM-6) and those that have both transmembrane and cytoplasmic domains (BGP splice variants). Studies have shown that CEA mediates Ca2+- and temperature-independent cell aggregation.10 Some studies have demonstrated that CEA is an intercellular adhesion mol ecule. However, other studies have shown that CEA may act as a signal protein that inhibits intercellular contact in the malignant process.11 In terms of its tissue distribution, biochemis try and molecular structure, CEA is one of the most well-characterized tumor associated anti gens (TAA). CEA is extensively expressed in the vast majority of human colorectal, gastric and pancreatic carcinomas, in approximately 50% of breast cancers and in 70% of non-small-cell lung cancers. To a lesser extent, CEA is also expressed on normal colon epithelium and in some fetal tissue. The relative tissue specificity of this antigen thus makes CEA a potential target
Peptide-Based Cancer Vaccines, edited by W. Martin Kast. ©2000 Eurekah.com.
