U937/Luciferase cells are derived from the human pro-monocytic cell line U937 by stably integration of a constitutive Firefly luciferase stably expression construct. U937 cells are able to differentiate into either dendritic cells or macrophages, depending on the surrounding signals. U937 cells are widely used for studies of monocyte/macrophage differentiation, the macrophage-tumor cell interaction and anti-cancer drug screening. U937/Luciferase cells stably express Firefly luciferase, can be used for in vitro assays and in vivo imaging.