In endometriosis, local proinflammatory mediators such as interleukin (IL)-1b and tumor necrosis factor- (TNF-) a stimulate the nuclear factor kB (NF-κB) and hypoxia inducible factor- (HIF-) 1a signaling pathways, increasing COX-2 expression [46]. The gene discussed is TNF; the disease is endometriosis.