ENG and neoplasm: Due to the role of endoglin in TGF-β signaling and decreased expression of endoglin in toxicarioside-A-treated HUVECs and TGF-β in the toxicarioside-A-treated CT26 and LL/2 tumor cells, we explored the roles played by endoglin and TGF-β in Smad signaling in HUVECs.