Gene expression profiling for molecular staging and prognosis prediction in colorectal cancer

A key issue for patients undergoing surgery for colorectal cancer is the accurate prediction of treatment outcome. Currently, classification of a tumor by histopathologic stage is the most accurate prognostic factor for the risk assessment of treatment failure. However, despite Improved histologic techniques and the application of novel immunohistochemical and molecular techniques, It Is still not possible to delineate the underlying biochemical and genetic events that predict clinical outcome for individual cancer patients. One reason for this lack of progress is that the factors which determine the metastatic potential of a primary tumor are still unknown. This reality, coupled to dramatic technological developments In the field of expression profiling, has started a paradigm shift In the staging of colorectal cancers. It has raised expectations that genetic and/or transcriptome profiling of the primary tumor will result in the Identification of prognostic determinants relevant to the individual patient. In turn, this may allow a clinically relevant definition of patient subgroups based on individual molecular parameters for rational decision making regarding choice of therapy.