Identification of differential gene expression between intestinal and diffuse gastric cancer using cDNA microarray.

To compare the gene expression profiling between intestinal-type gastric cancer (IGC) and diffuse-type gastric cancer (DGC), cDNA microarray containing 7334 gene elements was performed on 12 paired IGC specimens/its' normal epithelial tissue and 11 paired DGC specimens/its' normal epithelial tissue. Twenty-seven genes were co-overexpressed in IGC and DGC. These overexpressed genes were related to transcription and translation, DNA replications and mitosis, calcium binding, apoptosis and mitochondria protein. Twelve genes were co-underexpressed in IGC and DGC. These underexpressed genes were associated with cell adhesion and migration, organelle movement and intracellular transport, and matrix metalloproteinase. A clustering dendrogram of IGC and DGC with 27 genes significantly differed between IGC and DGC. Nineteen genes were more overexpressed in DGC than in IGC, including annexin A1 (ANXA1), chemokine ligand 7 (CCL7), and chemokine ligand 8 (CCL8). Eight genes were more overexpressed in IGC than in DGC, including claudin 4 (CLDN4). The results of quantitative real-time PCR and immunohistochemical staining confirmed the microarray finding. The gene expression profiling between IGC and DGC suggested that they might have unique genetic pathways which share some of the same and some different genetic alterations.