NCI-H441/STAT5 Reporter (GFP) cells are derived from the human NCI-H441 lung carcinoma cell line by stably integration of a STAT5 GFP reporter construct. NCI-H441 cell line is a useful model for understanding the complexities of lung cancer and for the development of new therapeutic strategies. NCI-H441/STAT5 Reporter (GFP) cells stably express GFP under the control of the STAT5 response elements, can be used for monitoring the activity of STAT5 signaling pathway.