Thus, as would be predicted from the studies on ABCG2 and ALDH1, AHR inhibitors increased the sensitivity of ER+ and ER- breast carcinoma cells to Adriamycin and Paclitaxel [162,199], oral cancer cells to Cisplatin [106,199] and choriocarcinoma cells to Methotrexate [197], directly connecting AHR-driven CSCs to cancer treatment outcomes. Here, ABCG2 is linked to lip and oral cavity carcinoma.