Phosphoproteomic analysis of diffuse-type gastric carcinoma cells with Met gene amplification identified Pleckstrin Homology Domain Containing A5 (PLEKHA5) as a protein that is tyrosine-phosphorylated downstream of Met. We used DNA microarray analysis to explore the signaling pathways downstream of PLEKHA5 that regulates the survival and peritoneal dissemination of Met-amplified 58As9 diffuse-type gastric carcinoma cells. Overall design: 58As9 cells were transfected with conrol or PLEKHA5 siRNA for RNA extraction and hybridization on Affymetrix microarrays.