In this study, we used a similar strategy to determine the properties of activated Smad complexes in different cell lines by identifying the DNA sequences bound to endogenous Smad complexes activated by TGF‐β in three target cell lines: A549 (human lung adenocarcinoma), HepG2 (human hepatoblastoma), and HaCaT (human normal immortalized keratinocytes). The gene discussed is TGFB1; the disease is hepatoblastoma.