TGFB1 and cervical cancer: In addition, the protein levels of TGF-β1 and TβRI and the phosphorylation levels of Smad2/3 (p-Smad2 and p-Smad3) were significantly increased in HeLa and SiHa cells, indicating that the TGF-β1/Smad2/3 pathway was activated in cervical cancer.