Biomarkers in gastrointestinal cancers

We have summarized the characteristics of the clinically useful or potentially useful biomarkers in a number of GI cancers. This field is growing, and the predictive and diagnostic value of the biomarkers as a measure of carcinogenesis is still in evolution. It is essential for the clinician to have an understanding of the basic molecular biology behind GI cancers because, in the future, many clinicians will be routinely ordering biomarker testing as part of patient screening. The biomarkers in GI cancers are useful not only for screening, diagnosis, and prognosis but also for prediction of the response to mechanism-based interventions, such as chemoprevention. Ongoing assessment of these diagnostic and predictive factors will probably lead to a change in the current staging of many GI cancers.