Reexpression of Smad4 in Smad4-deficient tumor cells led to secretion and deposition of the heterotrimeric molecule in BM-like structures and was associated with reversion from mesenchymal-like to epithelial morphology, with suppression of invasiveness in vitro and suppression of tumor growth in vivo [15-19]. The gene discussed is SMAD4; the disease is neoplasm.