There is a clinical demand for tools that could distinguish patients who may benefit or suffer from particular systemic treatments. High throughput technologies such as DNA microarray are anticipated as comprehensive tools for development of accurate predictive markers of treatment outcome. Although technical and statistical problems still exist in pharmacogenomic research, rigorous efforts have been made to realize treatment individualization. Clinicians should be prepared for the future use of these new technologies in the clinic through discussion involving patients and various health-care providers.