Endocan, also known as Endothelial Cell-specific Molecule-1 (ESM-1) and IGFBP-rp6, is a secreted cysteine-rich dermatan sulfate proteoglycan. It is primarily expressed by endothelial cells within the vascular network of the kidney and in the alveolar walls of the lung. Endocan expression is upregulated by TNF-alpha, IL-1 beta and LPS, and downregulated by IFN-gamma. Endocan binds LFA-1 on human lymphocytes, monocytes and Jurkat cells, inhibiting its binding to ICAM-1 and reducing LFA-1-mediated leukocyte activation. Elevated circulating Endocan levels have been reported in patients with lung cancer and severe sepsis.