CDH1 and gastric cancer: To confirm above signal transduction aberrations observed on differential gene expression profiling of c.1380delA SB.mhdgc.-1 and sporadic gastric cancer cells, we first measured intracellular phosphatidylinositol 4,5-bisphosphate (PIP2) levels, and its metabolite phosphatidylinositol 3,4,5-trisphosphate (PIP3), as intermediaries of inositoltrisphosphat (IP3)/diacylglycerol (DAG) signaling between c.1380delA CDH1 SB.mhdgc-1 and sporadic SB.msgc-1 gastric cancer cells.