CEACAM-6, previously called nonspecific crossreacting antigen (NCA) or CD66c, is a highly glycosylated 90 kDa, 286 aa, GPI-linked membrane protein of the human CEACAM family within the immunoglobulin superfamily. CEACAM-6 is an intercellular adhesion molecule, forming homotypic and heterotypic bonds with CEACAM-1, -5 and -8. Mature human CEACAM-6 shares 84% and 85% aa identity with human CEACAMs 1 and 5 (CEA). It is expressed in azurophilic granules in cells of the granulocyte lineage, and in epithelia of various organs.