TGFB1 and cancer: Western blotting analysis indicated that the levels of phosphorylated of Smad2 protein (p-SMAD2), p-SMAD3 and p-SMAD4were significantly elevated in CAF-CM and TGF-β1-treated cancer cells, suggesting that CAFs activated the TGF-β1/SMAD signaling pathway (Fig. 4a).