In thyroid-tumor samples, the AhR target genes CYP1A1 and CYP1B1 were upregulated relative to associated healthy tissue [15] and again Kyn stimulation of thyroid-cancer cell lines promoted the acquisition of an EMT program (decreased E-cadherin, and increased SLUG, N-cadherin, and fibronectin levels). This evidence concerns the gene CYP1A1 and thyroid cancer.