CD68

CD68 is a heavily glycosylated, lysosome-associated transmembrane glycoprotein of the scavenger receptor family, encoded by the CD68 gene, with predominant localization to lysosomal and endosomal membranes and a smaller fraction at the cell surface. The molecule is expressed by macrophages, monocytes, Kupffer cells, osteoclasts and dendritic cells and also by basophils, mast cells and some fibroblasts. Because tissue macrophages stain robustly, anti-CD68 immunohistochemistry is the routine marker for macrophage lineage identification, for scoring tumor-associated macrophage density in cancer specimens, and for diagnosing histiocytic neoplasms, although the protein is not macrophage-specific in all contexts.