CEA is a cell adhesion glycoprotein that is predominately expressed during fetal development.46 CEA is expressed in adult gastrointestinal tissues, predominantly at the luminal surface.47 Moreover, CEA is a common TAA that is overexpressed in most colorectal tumors48 and detection in serum is a useful biomarker for monitoring colorectal cancer progression.46 While the role of CEA in tumor development or progression isn’t clear, CEA can be a therapeutic target. This evidence concerns the gene CEACAM5 and colorectal cancer.