Other studies have shown that TGF-β1 reduces ESR1 mRNA expression [53, 54] and ESR1 protein expression [54, 55] in breast epithelial cancer cells and ESR2 protein expression in prostate cancer cells [51], however this is the first study to show that TGF-β1 reduced ESR2 and GPER1 mRNA expression and certainly the first to report any interaction between TGF-β1 and ESRs in bronchial epithelial cells. Here, GPER1 is linked to prostate cancer.