TGFB1 and neoplasm: For example, exosomes derived from chronic myeloid leukemia (CML) cells carry transforming growth factor-β (TGFβ1), which, in an autocrine manner, binds to the TGFβ1 receptor on CML cells, promoting tumor growth through activation of extracellular regulated MAP kinase (ERK), Akt kinase (AKT), and anti-apoptotic pathways (7).