AHR and breast cancer: Importantly, these findings on AHR-regulated genes appear generalizable since strong correlations were seen between Ahr or Cyp1b1 and the stem cell- and migration/invasion-associated gene sets in databases of 79 human breast cancer cell lines characterized in the CCLE and over 1850 primary human breast cancers catalogued in the TCGA and Curtis databases (Additional files 5 and 6: Figure S5 and S6).