Predictive and prognostic markers in gastrointestinal cancers

As the roles of specific genes and their functions in cancer etiology and p rogression become defined, the necessity of looking at multiple genes and t heir interaction becomes clearer, In gastrointestinal cancer, tumor suppres sor and promoter genes, cell cycle control and angiogenic factors, repair g enes, and metabolic genes have been examined as they relate to prognosis an d therapeutic outcomes. To date, most correlative studies for specific mole cular parameters have been done retrospectively. Methodologies, sample size s, and definitions differ. The following analysis provides a brief review o f the current state of knowledge and recent research on the most commonly s tudied molecular markers, and the newer areas of inquiry attempting to defi ne how to use molecular-genetic features of individual tumors as targets fo r more effective therapies. Consideration is given to the design of trials employing molecular targets as outcome factors. (C) 2001 Lippincott William s & Wilkins, Inc.