Real-Time Polymerase Chain Reaction Gene Expression Assays in Biomarker Discovery and Validation

Biomarkers have shown great potential in molecular classification and targeted treatment of human diseases. Biomarkers are also expected to play an increasingly important role in all phases of drug development as well as regulatory decision making. However, translating biomarker discovery into clinically useful tests in a time- and cost-effective manner remains a significant challenge. Real-time polymerase chain reaction (PCR) technology, in particular TaqMan^� -based real-time PCR gene expression assays, provides a simple, robust, and practical tool that has shown great potential in bridging the gaps between biomarker discovery and clinical practice. In this chapter, we will survey the principle of this technology and its wide applications in biomarker discovery and validation.