To evaluate the effect of the MSCs on cancer cells and track the transplanted cancer cells in vivo using imaging analysis, we constructed double imaging MDA-MB-231 cells (Fluc/GFP-pStat3/Rluc) with Fluc and eGFP reporter genes drived by a ubiquitin promoter, Rluc reporter gene drived by a seven-repeat Stat3-binding sequence (enhancer) and minimal TA (promoter) in response to the activated Stat3. The gene discussed is STAT3; the disease is cancer.