Kynurenine increased the expression of the AHR target genes cytochrome P450 family member 1A1 (CYP1A1), TCDD-inducible poly(ADP-ribose) polymerase (TIPARP), plasminogen activator inhibitor-2 (PAI-2), interleukin-1β (IL1B) and CYP1B1, but not of nicotinamide phophoribosyltransferase (NAMPT), which is not an AHR target and was used as negative control (Supplementary Fig 8B-G), indicating that kynurenine activates the AHR also in human ovarian carcinoma and lung cancer cells. This evidence concerns the gene IL1B and lung cancer.