Cell surface glycoprotein that plays a role in cell adhesion in a calcium-independent manner (PubMed:8776764, PubMed:2022629, PubMed:11590190). Mediates heterophilic cell adhesion with other carcinoembryonic antigen-related cell adhesion molecules, such as CEACAM6 (PubMed:8776764, PubMed:2022629, PubMed:11590190). Heterophilic interaction with CEACAM8 occurs in activated neutrophils (PubMed:8776764). Monomer. Heterodimer with CEACAM6; heterodimerizes via its Ig-like V-type domain. Expressed in leukocytes of chronic myeloid Leukemia patients and bone marrow. The N-terminus Ig-like V-type domain is necessary for heterophilic intercellular adhesion. Glycosylated. Belongs to the immunoglobulin superfamily. CEA family.