Regulation of TGF-β by retinoids has been demonstrated in various processes such as chondrogenesis44,45 and morphogenesis of the mammary gland.12 We have demonstrated an interaction between ATRA and the TGF-β pathway in leiomyomas by demonstrating ATRA down-regulation of TGF-β3 expression and expression of TGF-β regulated genes such as the MMPs. Here, TGFB1 is linked to leiomyoma.