Increased activation of macrophages, along with increased secretion and synthesis of different pro-inflammatory mediators, cytokines, tumor necrosis factor-α, interleukins, RANTES, platelet activating factors, fibroblast growth factors, hepatocyte growth factor (HGF), macrophage-derived growth factor, vascular endothelial growth factor, angiogenesis factor, and fibronectin has been reported at ectopic sites in women with endometriosis. The gene discussed is HGF; the disease is endometriosis.