TGFBR1 and osteosarcoma: Furthermore, lumican regulates adhesion of osteosarcoma cells by modulatingTGF-β2/Smad2 signaling pathway.141 Although the exact mechanisms of lumican inhibition of TGF-β2 signalingare still unclear, it is known that lumican directly binds to TGFβR1 (ALK5) andpromotes epithelium wound healing.143 The consequences of lumican–TGFβR1 complex formation on the binding ofTGF-β to TGFβR and TGF-β downstream signaling require further investigations.