The research focuses on tumor growth in the digestive tract and chronic inflammatory conditions that can predispose to cancer. Our understanding of tumorigenesis in the gastrointestinal tract has increased profoundly in recent years. Molecular genetic alterations are the cause of tumor growth and they also largely determine the natural history of these neoplasms. Tumorigenesis in the colorectum serves as a paradigm for neoplastic growth of solid human tumors in general. Tumorigenesis is a multistep process in which subsequent stages are accompanied by an accumulation of generalized and specific genetic alterations. Ultimately this cascade of genetic events leads to autonomous and invasive growth with metastatic potential. Different classes of genes are involved in this neoplastic process, such as oncogenes, tumor suppressor genes, mutator genes and genome maintenance genes. Many of these specific genes have been identified in recent years, but this explosive growth in knowledge has as yet not been translated in a simultaneous increase in practical applications from which patients would benefit. The research in our group attempts to translate the recent molecular genetic advances into practical applications in order to improve diagnosis, prognostication, therapy and risk assessment for tumors of the digestive tract. In the esophagus molecular markers are studied in Barrett esophagus for more accurate grading of dysplasia. An attempt is made to develop gene therapy for Barrett carcinoma. The molecular genetics of gastric carcinogenesis are studied in order to delineate tumor progression more precisely in the stomach. Early onset gastric cancer is studied to detect potential hereditary predisposing factors for the development of stomach cancer. The value of molecular markers for an early diagnosis of pancreatic cancer are investigated on brush cytology samples collected from the pancreatic duct. Risk factors for the development of pancreatic cancer are studied. In the colorectum the molecular genetics of polyposis syndromes leading to cancer are studied, and potential mechanisms for chemoprevention of these tumors are under investigation.