SMAD4 and chondrosarcoma: To determine which components of the TGF-β/BMP signalling pathway were responsible for the high activity of SMADs in chondrosarcomas, we examined the expression profiles of TGF-β ligands, BMP ligands, TGF-β type I receptors, BMP type I receptors, TGF-β-regulated R-SMADs, SMAD4, and BMP-regulated R-SMADs (Supplementary Fig. S1a–g).