Gene expression profiling to dissect the complexity of cancer biology: Pitfalls and promise

Despite advances in chemotherapy, hormone therapy and radiotherapy, not all cancer patients respond favorably to treatment. However, progress in understanding the mechanisms of malignant diseases and the mode of action of therapies are opening opportunities to match treatment to specific patient subpopulations, paving the way for personalized medicine. In this context, high throughput technologies that have been developed to determine gene expression profiles potentially offer an effective tool for dissecting the biology of cancer pathologies, for identifying candidate molecules for the development of new drugs, and for identifying individual patients who are more likely to respond favorably to a given therapy. Here, we overview and discuss the robustness of the deployment of these technologies in these contexts. We conclude that while these technologies are useful for target identification, there are limitations to their use in understanding cancer biology and in routine clinical application.