Here, epidermal growth factor (EGF), vascular endothelial growth factor, interleukins (IL-1β, IL-6, IL-8), macrophage migration inhibitory factor (MIF), calcitonin gene-related peptide, and somatostatin were measured in the serum of endometriosis patients with different disease severities, menstruation cycle- and pharmacotherapy-related hormonal status compared with controls. This evidence concerns the gene CXCL8 and endometriosis.