CEACAM1 also konwn as CD66A is a member of the carcinoembryonic antigen (CEA) gene family, which belongs to the immunoglobulin superfamily. CEACAM1 plays a crucial role in cell adhesion and signaling processes. CEACAM1 is particularly important due to involvement in the modulation of immune responses and potential role in tumor suppression, as CEACAM1 is underexpressed in colorectal cancers. CEACAM1 exists in several alternatively spliced isoforms, some membrane-bound while others secreted, allowing for diverse functional roles in different cellular contexts. CEACAM1 contains one immunoglobulin-like V-type domain and three C2-type domains, which contribute to structural integrity and functional versatility.