Estrogen receptor (ER) and AhR signaling crosstalk can have inhibitory effects on AhR ligand and ER ligand activity, as reviewed extensively by Matthews and Gustafsson.62 The ER and the AhR are ligand-activated transcription factors that upon ligand binding, lead to receptor recruitment to either estrogen-response elements or xenobiotic-response elements of target genes.62 Matthews et al. also showed that when the AhR is active, it can redirect ER from ER target genes to bind AhR target genes.63 This suggests that the AhR can regulate the ER as well as estrogenic responses in BC cells. Here, ESR1 is linked to breast cancer.