Oxidative stress is a common factor between IDO activity, kynurenine metabolism and the activity of NFκB, inflammatory cytokines, TNF, nuclear factor erythroid 2-related factor 2 (Nrf2) and COX-2, with expression of all of these being modulated by the antioxidant indole CMI (3-(4-chlorophenyl)selanyl)-1-methyl-1H-indole (CMI) in mammary-tumor-bearing mice [193]. This evidence concerns the gene NFE2L2 and breast cancer.