SMAD2 and lung cancer: TAMs were also found to directly support tumor stemness by secreting other cytokines, such as the TGF-β1/smad2/3 pathway in pancreatic cancer [220] or the TGF-β1/integrin αvβ5/Src/STAT3 pathway and TGF-β2/smad2/3 in glioblastoma [180, 221], as well as MFG-E8/STAT3 and Hedgehog signals in lung cancer [222].