These findings, which are originally often based on translational research results23–25are also reflected by numerous diagnostic studies focusing for example on the pro- inflammatory cytokine IL-6 in patients with endometriosis; IL-6 is produced by macrophages, which are among the most prevalent cell types within endometriomas and are frequently observed in close proximity to peritoneal ectopic endometrial lesions. This evidence concerns the gene IL6 and endometriosis.