In vivo bioluminescent imaging (BLI) is progressively becoming a widely utilized method for modern biological research. The noninvasive character of this method using light emitted from luciferase-expressing bioreporter cells is applicable to living animals, and has been used to study a wide range of biomolecular functions such as gene function, drug discovery and development, cellular trafficking, protein-protein interactions, and especially tumorigenesis, cancer treatment, and disease progression. Firefly luciferase (FLuc) is the best studied of a large number of luminescent, and catalyzes the oxidation of reduced luciferin in the presence of ATP-Mg2+ and oxygen to generate CO2, AMP, PPi , oxyluciferin, and yellow-green light at a wavelength of 562 nm.