CEACAM20 is an immunoglobulin superfamily transmembrane protein expressed in intestinal epithelium, testes, and prostate tissue 1. Its primary function involves enhancing intestinal immune responses through cytokine production. Specifically, tyrosine phosphorylation of CEACAM20 by c-Src kinase facilitates its association with spleen tyrosine kinase (Syk), promoting IL-8/CXCL8 production via NF-κB pathway activation 2. CEACAM20 contains an immunoreceptor tyrosine-based activation motif (ITAM) in its cytoplasmic domain; phosphorylation at Tyr559 and Tyr570 residues within this motif is critical for function 3. Beyond immune signaling, CEACAM20 regulates phagocytic activity through Src family kinases, PI3K, and PLCγ pathways requiring actin polymerization 3. In tissue architecture, CEACAM20 is restricted to acini structures and plays an essential role in prostate lumen formation 1. The protein tyrosine phosphatase SAP-1 dephosphorylates CEACAM20, providing negative regulation that protects against intestinal inflammation; SAP-1 ablation exacerbates colitis through CEACAM20 hyperphosphorylation 2. Transcriptional analysis indicates CEACAM20 downregulation in colorectal cancer cells treated with antitumor agents 4, suggesting potential involvement in cancer biology. CEACAM20 represents a conserved family member with distinct tissue-specific expression patterns 5.