SMAD2 and liver dysplastic nodule: Oujo et al. (2014) found an increase in SMAD2/3 phosphorylation in the tubular interstitium but not in tubular cells, suggesting that SMAD2/3 phosphorylation is related to changes in interstitial myofibroblast cells rather than in epithelial cell function. Also, a meta-analysis of randomized controlled trials revealed that serum TGF-β1 could act as a biomarker for DN (Mou et al., 2016).