TGFB1 and neoplasm: The activation of TGF-β signalling led to increased downstream gene expression, as indicated by the correlation of SMAD7 expression—a typical SMAD-positively regulated gene—with TGFB1 in human iCCA (Supplementary Fig. 2b) and the increased Smad7 mRNA expression in tumours from the mouse iCCA models (Supplementary Fig. 2c).