To determine the efficacy of TGF-β specific inhibition, we investigated the effects of TGF-β neutralizing antibody 1D11 on exogenous TGF-β induced Smad2 phosphorylation, a first required step in TGF-β signaling, and transcription of TGF-β target gene PAI-1 in AML cells. Here, TGFB1 is linked to acute myeloid leukemia.