Chemokine (C-X-C-Motif) Ligand 6 (CXCL6) is a small cytokine belonging to the CXC chemokine family. It is a potent neutrophil chemotactic and activating factor and it exhibits extensive similarity to other CXC chemokines such as IL-8 and ENA-78. CXCL6 can promote the release of MMP-9 from granulocytes indicating its potential role as an inflammatory mediator. It functionally uses both of the IL-8/CXCL8 receptors to chemoattract neutrophils but that is structurally most related to epithelial cell-derived neutrophil attractant-78 (ENA-78)/CXCL5. The human CXCL6 gene has been cloned and is physically mapped to the CXC chemokine locus on chromosome 4. Mature human CXCL6 is a 75 amino acid (aa) protein with a predicted molecular weight of approximately 8 kDa. Human CXCL6 shares 60% and 67% aa identity with mouse and bovine CXCL6, respectively.