TGF-β1 Is Expressed on CML Exosomes. (a) Western blot analysis shows that LAMA84-derived exosomes express TGF- β1. Loading was based on equal protein amount (upper panel). LAMA84 cells express TGF- β1 receptor (lower panel). (b) After 72 or 96 hours of treatment of LAMA84 with 10 μg/ml of LAMA84-exosomes there is an increase in the phosphorylation of the downstream target of TGF-β1, SMAD 2/3; the treatment does not alter the total level of the protein.