[Molecular-pathological diagnosis of gastric cancer]

Gastric cancer is one of the most common human cancers and is the second most frequent cause of cancer-related death in the world. In the course of multistep carcinogenesis of the stomach, various alterations of oncogenes, tumor suppressor genes, DNA repair genes, growth factors/receptors, cell cycle regulators and cell adhesion molecules are accumulated. These can be biological markers of malignancy for molecular-pathological diagnosis. The gene expression profile and scoring system, based on microarray analysis, have great potential for differentiating the character of gene expression in individual cancers and predicting biological behavior and chemosensitivity. Genetic polymorphism is an important determinant of the endogenous cause of cancer and can be used as a marker for gastric cancer risk that will directly connect with personalized cancer prevention. Genetic polymorphisms have been also associated with therapeutic efficacy and toxicity of anti-cancer drugs. Serial analysis of gene expression (SAGE) is a powerful technique to allow genome-wide analysis of gene expression in a quantitative manner. By comparing SAGE libraries of gastric cancer with those of various normal tissues, novel genes specifically expressed in gastric cancer can be selected. If the gene is not expressed in normal crucial organs, the gene can be not only a cancer-biomarker but also a therapeutic target with minimal adverse effects. A custom-made array, based on SAGE libraries, is useful to study the molecular pathogenesis of gastric cancer and obtain information on biological behavior. Combined analyses of gene expression profile and genetic polymorphism will enable the characterization of the individual cancer and person, that is directly connected with personalized medicine and cancer prevention.