To confirm that BM-MSCs do not induce the canonical TGF-β pathway in AML cells, we measured phosphorylation of Smad2 and Smad3 in OCI-AML3 cells treated with recombinant TGF-β1 and still could not find any activity for these 2 proteins (Fig 4E). The gene discussed is TGFB1; the disease is acute myeloid leukemia.