Platelets play a critical role in endometriosis-associated fibrogenesis: activated platelets within lesions release numerous growth factors, cytokines, and chemokines such as TGF-β1, platelet-derived growth factor (PDGF), epidermal growth factor (EGF), and connective tissue growth factor (CTGF). The gene discussed is TGFB1; the disease is endometriosis.