HER2 overexpression-mediated inflammatory signaling enhances mammosphere formation through up-regulation of aryl hydrocarbon receptor transcription

► HER2 overexpression enhances AhR mRNA and protein levels. ► HER2/MEK/ERK signal increases transcription of AhR mRNA. ► AhR Inhibition reduces HER2-mediated induction of IL-6 mRNA and mammosphere formation. ► Results suggest HER2/AhR signaling is important for maintenance of cancer stem cells in HER2-overexpressing breast cancer cells.