Molecular testing of gastrointestinal tumours.

Cancers of the gastrointestinal tract are a major cause of morbidity and mortality globally and, not surprisingly, there has been intense interest in identifying prognostic and predictive markers for new targeted therapies. The cancers of the gastrointestinal tract are unique in so completely exemplifying many of the key features of biomarker profiling across all solid cancers. Firstly, they involve the assessment of many individual biomarkers of many types, with both genomic and proteomic markers requiring assessment for complete profiling. Secondly, the interpretation of one biomarker is often critically dependent on the presence or absence of other biomarkers. And finally, this vast array of testing must be delivered often on very small samples. Here, we review the clinically-validated molecular targets in carcinomas of the esophagus, stomach, colorectum and anal canal, and in gastrointestinal stromal tumors, and discuss a handful of markers which are likely to be of use in the future. [ABSTRACT FROM AUTHOR]