MRC5/STAT3 Reporter (Luc) cells are derived from he human fibroblast cell line MRC5 by stably integration of a STAT3 firefly luciferase reporter construct. MRC5 cells are widely used in the studies of cell biology, virus biology, cellular aging and toxicology. MRC5/STAT3 Reporter (Luc) cells stably express firefly luciferase under the control of the STAT3 response elements, can be used for monitoring the activity of STAT3 signaling pathway.