PPD is used to treat endometriosis and has been shown to significantly upregulate endometrial receptivity-related molecules, such as interleukin 6 family cytokine, insulin-like growth factor-binding protein 1, and collagens, to restrict the pelvic macrophage inflammatory response and to recover fertility in mice with endometriosis. The gene discussed is IGFBP1; the disease is endometriosis.