ALCAM/CD166

ALCAM/CD166 is a transmembrane member of the immunoglobulin superfamily encoded by the ALCAM gene, carrying five extracellular Ig-like domains that mediate both homophilic ALCAM binding and heterophilic binding to CD6. Expressed on activated leukocytes, thymic epithelial cells, neurons and many epithelia, it supports T cell-dendritic cell interactions and contributes to thymic T cell selection. ALCAM is a recognized marker of mesenchymal stromal cells and of epithelial stem-like compartments, and its upregulation in colorectal, ovarian, pancreatic and melanoma tumors correlates with invasiveness and poor outcome. Soluble ALCAM has been explored as a circulating biomarker in oncology and inflammation.