AHR and breast carcinoma: Notably, the AhR was expressed in both cytoplasm and nucleus in AFP464-sensitive ERα-positive luminal subtype breast cancer cell lines (MCF-7 and SUM44), and it was predominantly expressed in the cytoplasm in AFP464-sensitive ERα-negative basal A subtype breast cancer cell lines (MDA-MB-468 and BT20) (Figure 1).