TGFB1 and Hepatic fibrosis: In fact, a derivative of ATRA has been shown to inhibit TGF-β-induced liver fibrosis by suppressing the collagen (COL) 1A2 gene [21]; additionally, an isomer of ATRA, 9-Cis-retinoic acid (9-Cis-RA), was found to attenuate TGF-β-induced fibrotic changes in cultured human mesangial cells [20].