TGF-β, one of the central fibrotic factors, plays a major role in the trans-differentiation of interstitial fibroblast to myofibroblast during renal fibrosis by activation both canonic and non-canonic signaling pathways which involve smad2/3 and MAPK proteins, respectively (Geng et al., 2019). The gene discussed is SMAD2; the disease is renal fibrosis.