BMPR1A and gastric neoplasm: Since epithelial deletion of Bmp signaling is not sufficient to induce gastric tumor formation, we developed a genetically-modified mouse model to inactivate the Bmp type 1a receptor (Bmpr1a) specifically in the gastrointestinal sub-epithelial mesenchyme in order to specify the function of the mesenchymal Bmp signaling cascade in gastric tumorigenesis initiation.