The carcinoembryonic antigen (CEA) family is composed of 29 genes tandemly arranged on chromosome 19q13.2. Based on nucleotide homologies, these genes are classified into 2 major subfamilies, the CEACAM and the pregnancy-specific glycoprotein (PSG) subgroups. The CEACAM-encoded proteins include CEA, CEACAM1, and other CEA gene members (1). CEACAM1 (Carcinoembryonic antigen related cell adhesion molecule 1, also BGP1, CD66a), is involved in the regulation of important biological processes, such asinsulin homeostasis (2) , angiogenesis (3), and modulation of the immune response (4). Expression of CEACAM1 is associated with the progression of malignancy and metastatic spread in a large array of cancer tissues which include melanoma, Non Small Cell Lung Carcinoma (NSCLC) bladder, prostate, thyroid, breast, colon and gastric carcinomas (5). In addition, CEACAM1 has also been identified as receptors for host-specific viruses and bacteria in mice and humans such as Neisseria, Haemophilus influenzae, Moraxella catarrhalis and mouse hepatitis virus (MHV) (6,7). The binding of Opa (the neisserial colony opacity associated) proteins occurs at the non-glycosylated face of the N-domain of CEACAM1 (8), heterophilic adhesion facilitates bacterial colonization of the gut and bacterial phagocytosis by neutrophilis, and is involved in the granulocytes migration during inflammatory responses. The N-terminal domain of CEACAM1 has been implicated also in mediating homophilic adhesion (9). This is an important factor for the embryonic organization of the intestinal epithelium and hepatocytes in the liver, in placental trophoblasts, during muscle and tooth development and vascularisation of the central nervous system, in angiogenesis and in the negative regulation of cell proliferation.