TGFB1 and breast carcinoma: Interestingly, exosomes isolated from tumor cells of a mouse model of breast cancer exhibited immune suppression activity inducing bone marrow derived CD11b+Gr-1+ cells to differentiate in myeloid-derived suppressor cells (MDSCs), known to promote tumor progression, via prostaglandin E2 (PGE2) and TGF-β pathways [58].