TGFB1 and glioblastoma: TGF-β is a strong angiogenic factor110–114 that is greatly overexpressed in GBM cell lines driven to resistance to bevacizumab115, further supporting the hypothesis that DCN expression and presence in the extracellular environment may increase survival in patients with recurrent GBM through prolonged resistance to bevacizumab by obstructing pro-angiogenic escape pathways.