Molecular and cellular biology of pre-malignancy in the gastrointestinal tract

Important pathogenic alterations within established cancers are acquired du ring the premalignant stage. These genetic alterations can be grouped into specific neoplastic pathways that differ within and between anatomical site s. By understanding the mechanisms that determine the initiation and progre ssion of each pathway, it will be possible to develop novel approaches to t he diagnosis, prevention and treatment of cancer. This chapter outlines the principles underlying the molecular characterization of pre-malignant lesi ons, taking colorectal neoplasia as the main model.