CXCL8 and endometriosis: Neutrophils aggravate endometriosis mainly through the expression of pro-inflammatory cytokines such as interleukin 8 (IL-8 or CXCL8), C-X-C motif chemokine ligand 10 (CXCL10) and vascular endothelial growth factor (VEGF), which may promote disease progression [31,32].