The CXCL5 gene at 4q13.3 codes for C-X-C motif chemokine 5 a 114 amino acid peptide that is further processed before release. It is the chemokine that appears to mediate pain in sunburn and some other forms of local tissue injury and activates neutrophils. There are cleavage sites at amino acids 44 and 45 that produce the peptides ENA-78(8-78) and ENA-78(9-78) which are more biologically active. It has been associated with metastatic malignancy and atherosclerosis. Interleukin-1 or tumour necrosis factor alpha stimulate its secretion by cells, and also production of interleukin-8 which is also coded in the same chromosome region and has some sequence homology.