TGFB1 and glioma: Hjelmeland et al. [25] have shown that secretion of activated TGF-β1 is a common attribute of glioma cells (U-87 MG, U-373 MG, D-54 MG, D-270 MG, D-423MG, D-538 MG), while simultaneous release of TGF-β2 was found onlysporadically (D-54 MG, U-373 MG, D-423 MG).