GRO/MGSA/CXCL1 has chemotactic activity for neutrophils. It may play a role in inflammation and exerts its effects on endothelial cells in an autocrine fashion. All three isoforms of GRO are CXC chemokines that can signal through the CXCR1 or CXCR2 receptors. GRO expression is inducible by serum or PDGF and/or by a variety of inflammatory mediators, such as IL-1 and TNF, in monocytes, fibroblasts, melanocytes and epithelial cells. In certain tumor cell lines, GRO is expressed constitutively.