Luckily, we found that this plasmid could effectively express miR-7 in human lung cancer cells with a higher expression level of TTF-1 in vitro, but not other human cancer cells with a lower expression level of TTF-1, including colon cancer, hepatocellular carcinoma, and gastric cancer, indicating that the TTF-1 promoter could effectively orchestrate targeted expression of miR-7 in lung cancer cells. Here, TTF1 is linked to lung cancer.