SMAD2 and lung cancer: The silencing of HSP27 enhances an additive effect with TGF-β1-induced EMT and the TGF-β1-induced HSP27 increase is not affected by the suppression of Smad2 and Smad3 in A549 cells, which suggests that HSP27 is involved in TGF-β1-induced EMT in a Smad-independent manner in lung cancer cells25.