To shed light on mechanisms that underlie development and/or progression of intestinal-type gastric cancer, we compared expression profiles of cancer cells obtained by laser-capture microdissection of 20 intestinal-type gastric tumors with expression of genes in corresponding noncancerous mucosae, by a cDNA microarray consisting of 23,040 genes. We identified 61 genes that were commonly up-regulated and 63 that were commonly down-regulated in the cancer tissues. Altered expression of 12 of those genes was associated with lymph node metastasis. A "predictive score," based on expression profiles of five of the genes that were able to distinguish tumors with metastasis from node-negative tumors in our panel, correctly diagnosed the lymph node status of nine additional gastric cancers. This genome-wide information contributes to an improved understanding of molecular changes during the development of intestinal-type gastric cancers. It may help clinicians predict metastasis to lymph nodes and assist researchers in identifying novel therapeutic targets for this type of cancer.