To establish an in vitro system in which to study our hypothesis we first evaluated the response of three NSCLC cell lines (H1299, H157 and A549) to TGF-β by measuring SMAD2 phosphorylation and its inhibition by cell exposition to the specific inhibitor of the TGF-β receptor Type I kinase SB431542, or to P144, a TGF-β-binding inhibitory peptide obtained from the sequence of the human TGF-β receptor type III (beta-glycan). Here, SMAD2 is linked to non-small cell lung carcinoma.