Carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1), also known as CD66a, is a member of the carcinoembryonic antigen (CEA) gene family within the immunoglobulin superfamily. The highly glycosylated CEACAM1 consists of an N-terminal V-type Ig-like domain, three C2-type Ig-like domains, an ITIM motif, and an intracellular calcium-binding site. CEACAM1 is a surface glycoprotein expressed in various blood cells, epithelial cells, and vascular cells. It serves as an adhesion molecule present in granulocytes, epithelial cells, and endothelial cells and mediates cell adhesion through homophilic and heterophilic interactions. Research has shown that CEACAM1 plays a role in multiple cellular processes, including tissue differentiation, angiogenesis, apoptosis, metastasis, innate immunity, and adaptive immune response regulation.