We performed BMP/Smad1/5-response element (BRE)-luciferase reporter assays by transfecting BMPR2 short form, with or without mutations in the ECD, into HepG2 cells, an immortal human cell line from liver carcinoma, or 2H-11 cells, an immortalised mouse endothelial cell line, alongside β-Gal transfection controls (Fig. 9a, b). Here, SMAD1 is linked to hepatocellular carcinoma.