CXCL8 and endometriosis: For example, excessive production of prostaglandin E2 and cytokines such as TNFα, IL-1β, IL-6, IL-8, IFNγ, and MCP-1 is observed in endometriosis lesions [137], while low expression of PR-B (acting as an anti-inflammatory agent) is found in both conditions [138, 139].