TGFB1 and acute myeloid leukemia: Nevertheless, a pro-peptide isoform of TGF-b comprised of the LAP covalently bound to mature TGF-b (~ 50 kDa) has also been reported on AML exosomes (99), and this latent form of TGF-b was shown to be dissociated following treatment with urea, further increases soluble TGF-b levels [85].