SMAD3 and Bloom syndrome: 2014; Tran et al. 2019; Yao et al. 2019; Chale-Dzul et al. 2020; Hussein et al. 2020; Li X-F et al. 2020; Du J-K et al. 2021). As shown in Figure 3(A,B), the transcript levels of TGF-β1 and protein levels of p-Smad2, p-Smad3 and Smad4 were increased in the lung tissue of BLM-treated mice compared with the control, suggesting that BLM activates TGF-β1-Smad signalling in the lung.