Luciferase, a bioluminescent oxidoreductase enzyme, catalyzes photon emission (400-620nm) through oxidation of its luciferin substrate. Its ultra-high sensitivity (detecting gene expression at single-cell resolution) and zero endogenous background establish it as a core reporter tool in oncology research. The broad dynamic range (linear correlation between signal intensity and cell number/gene activity) supports studies on weak promoters and microRNA regulation, while superior in vivo penetration (red-shifted mutants >600nm wavelength reach 3-4cm depth) enables non-invasive real-time monitoring of tumor metastasis, drug response, and PROTAC degradation kinetics. Dual-reporter systems (Firefly + Renilla) ensure precise dissection of cancer pathway mechanisms via internal normalization, and bioluminescence imaging (BLI) quantifies therapeutic efficacy in xenograft models.