CXCL8 and neoplasm: In fact, recent reports have demonstrated that hypoxia enhances the expression of vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) in tumour cells, resulting in an increase of metastatic potential (Claffey and Robinson, 1996; Shi et al, 1999; Biroccio et al, 2000).