TGFB1 and glioblastoma: Exposure of GBM cells to TGF‐β upregulated fibronectin and COL5A1 mesenchymal markers, leading to an aggressive behavior characterized by increased neurosphere formation and spindle‐shaped morphology and a more scattered growth pattern and this effect was reversed with TGF‐β inhibition.[36] Mechanistically, TGF‐β induces ZEB1 activity through SMAD2 phosphorylation, causing increased aggressiveness/invasiveness.[36] Canonical TGF‐β dependent mesenchymal transition is also confirmed by other studies.