AHR and cancer: Whereas AHR signaling driven by endogenous and dietary ligands, such as tryptophan metabolites and indoles, contributes to proper organ development and maintains cell and tissue homeostasis, a long-lasting activation of AHR by environmental chemicals may contribute to a variety of adverse health effects, including autoimmune and allergic inflammatory diseases, endocrine disruption and cancer (Murray et al., 2014; Roman et al., 2018; Rothhammer and Quintana, 2019; Stockinger et al., 2021; Vogel et al., 2020).