For example, Figure 3 shows that mexiletine induces CYP1A1 mRNA in MDA-MB-468 (minimal) and BT47 breast cancer cells (Figure 3A); however, in these same cell lines mexiletine exhibits partial AhR antagonist activity and inhibits TCDD-induced CYP1A1 mRNA in MDA-MB-468 cells (Figure 3B). This evidence concerns the gene CYP1A1 and breast carcinoma.