[The impact of gene expression profiling in pathology]

With the introduction of high throughput methods for the parallel detection of the activity of many thousands of genes, a new dimension was opened. Meanwhile almost all types of tumor entities have been investigated by this technique leading to molecular gene expression signatures which were able to subdivide even histological uniform tumor entities. The correlation of the molecular signatures with the retrospective clinical data demonstrated in many instances that these molecular subdivisions provided meaningful results. Therefore the question arises as to whether this molecular characterization should also become a part of the diagnostic routine work. Before this question can be finally answered the impact of the molecular signatures should be confirmed in prospective clinical trials. Furthermore, the results of the high throughput technologies has to be adapted to order to be applicable to RNA extracted from formalin-fixed tissue specimens. This development has already started and should be performed within the pathologies.