AHR and breast cancer: Similar results were observed in MDA-MB-231 cells cotreated with omeprazole and the AHR antagonists 3′,4′-methoxy-α-naphthoflavone (Figure 2B) [29] and 3′-methoxy-4′-nitroflavone (Figure 2C) [30], further confirming a role for the AHR in mediating the inhibitory effects of omeprazole on MDA-MB-231 breast cancer cell invasion.