AHR and breast cancer: These data also offer an explanation for the observed decrease of mammary tumors in female rats after long-term treatment with TCDD (Kociba et al. 1978) and for the well-known inhibitory properties of exogenous AHR ligands on rodent mammary gland tumors and metastasis development (Lubet et al. 2011; Safe 2001; Wang T et al. 2011).