KATO III/Luciferase cells are derived from human gastric cancer cell line KATO III by stably integration of a constitutive Firefly luciferase stably expression construct. KATO III cells are valuable for studying gastric cancer biology, including the mechanisms of tumor growth, metastasis, and response to therapies. KATO III/Luciferase cells stably express Firefly luciferase, can be used for in vitro assays and in vivo imaging.