CD68 is a transmembrane glycoprotein which acts as a commercialized marker for human monocytes and macrophages. Its expression is thought to be regulated by a macrophage-specific promoter. However, several immunohistochemical studies have indicated that CD68 antibodies also react with other haematopoietic and non-haematopoietic cell types. It also can stain myeloid cells, dendritic cells, fibroblasts, Langerhans cells and others. In human monocytes, which produce high levels of CD68 mRNA, the gene is characterized by intramolecular ligations between the promoter and the 3' intervening region. CD68 is also used as a pan-macrophage marker for TAM (Tumor-Associated Macrophages) which always involve in carcinogenesis.