AHR and leukemia: Interestingly, the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, can enhance RA-mediated differentiation in myeloblastic leukemia cells [10], and the physiological AhR ligand 6-formylindolo[3,2-b]carbazol (FICZ) enhances differentiation in these leukemia cells [11].