SMAD2 and lung cancer: Among them, some studies (5 papers) have reported that BBR inhibits EMT through the TGF-β/Smad pathway, 3 of which (1 for intestinal cancer, 2 for lung cancer) considered that the TGF-β pathway promoted cancer metastasis and EMT, and BBR including its derivatives reduced p-Smad2, p-Smad3 and inhibited EMT.