CROa is a member of the a (CXC) family of chemokines. It is produced by monocytes, neutrophils, mast cells, epithelial cells, endothelial cells, keratinocytes and tumor cells. GRO expression is inducible by serum or PDGF and/or by a variety of inflammatory mediators, such as IL-1 and TNF. GROa is a chemoattractant for neutrophils, lymphocytes, monocytes, and epidermal melanocytes.