The tumor suppressing role of TGF-β/SMAD pathway seems particularly critical in the gastro-intestinal tract, since large subsets of pancreatic, gastric, and colon cancers carry mutations or deletions in TGF-β receptors or SMADs (Grady et al., 1999; Markowitz et al., 1995; Myeroff et al., 1995; Parsons et al., 1995; Schutte et al., 1996; Hahn et al., 1996; Schutte et al., 1996; Yakicier et al., 1999). The gene discussed is TGFB1; the disease is neoplasm.