AHR and cancer: Our results show that the AHR is involved in the control of phenotypic, genomic, and functional cancer stem cell markers in ER−/PR−/Her2− cells, strongly implicating an important role for the AHR in acquisition of stem cell-like qualities, encouraging development of AHR-targeted therapeutics, and raising the possibility that environmental AHR ligands may drive BCSLC development or activity.