PGR and endometriosis: The role of GnRH analogues  has been shown to induce apoptosis and reduce angiogenesis by increasing the expression of Bax and Fas-ligand (FasL) and decreasing Bcl-2, VEGF-A and interleukin-1 beta (IL-1β) in eutopic endometrial cell cultures [35]. Dienogest  is a novel progestin that is highly selective for progesterone receptors and inhibits endometriosis.