Further, the synthetic triterpenoid 1[2-cyano-3,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im), a known Nrf2 inducer, significantly reduced lung oxidative stress, alveolar destruction and emphysema caused by chronic CS exposure [95]. This evidence concerns the gene NFE2L2 and Cowden syndrome 1.