Targeted cancer therapy aims to block key signaling pathways that are critical for tumor cell growth and survival. The blockage eventually results in cell death via apoptosis and eventual tumor growth suppression. This strategy has proven to be quite effective, and the FDA has approved several targeted therapeutics in the past decade. Encouraged by the success in clinical development, many academic and pharmaceutical researchers are in active pursuit of improved next generation targeted anti-cancer drugs. As a result, many new chemical and biological entities are emerging from initial screening of in vitro, in vitro and/or in silico selection processes. From the perspective of drug development, it poses a great challenge for the next stage of in vivo validation and demands a robust, accurate, and efficient method for assessment of these candidates in living animal models.