TGFB1 and cancer: Such AhR effects may then be co-ordinated with decreased melatonin production across cells, leading to the loss of melatonin’s suppression of TGF-β as found not only in cancer cells [33], but also in fibrosis where melatonin’s suppression of TGF-β is a major inhibitor of fibrosis, across different organs and tissues [34,35].