Although it has been well-established that miR-206 directly targets the 3’ UTR of ESR1/ERα in ER+ breast cancer cells [1, 11, 12], Adams et al. (2007) identified a feedback mechanism where estradiol and other ERα agonists can significantly inhibit miR-206 expression, while ERβ agonists promoted miR-206 expression (Fig. 1a) [13]. This evidence concerns the gene ESR1 and breast carcinoma.