Women affected by endometriosis are more likely than those who were not affected by it to have higher levels of proinflammatory cytokines such as interleukin-1 beta (IL-1), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) occurring locally, in the peritoneal cavity, and systemically (20, 21). The gene discussed is TNF; the disease is endometriosis.