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). The gene discussed is PRRT2; the disease is neoplasm.