Carcinoembryonic Antigen-Related Cell Adhesion Molecule 8 (CEACAM8) is a single chain，GPI-anchored，highly glycosylated protein which belongs to the immunoglobulin superfamily and the carcinoembryonic antigen(CEA) family. CEACAM8 is expressed by neutrophils and eosinophils，and serves as a binding partner for CEACAM-6 and Galectin-3. It contains two Ig-like C2-type (immunoglobulin-like) domains and one Ig-like V-type (immunoglobulin-like) domain. Mature human CEACAM8 is a 287 amino acid GPI-linked glycoprotein. CEACAM family members are a set of widely expressed proteins involved in several biological functions，including cell adhesion，migration，signal transduction，and the regulation of gene expression. Abnormal overexpression and downregulation of some CEACAMs have been described in tumor cells.