Then the relative gene and protein expressions of let-7f and its target genes, including HMGA2, ARID3B, SMARCAD1, and FZD3, were measured in lung tissues of Non-Small Cell Lung Cancer (NSCLC) patients and A549 cell line using quantitative real-time PCR and Western blotting. The gene discussed is HMGA2; the disease is non-small cell lung carcinoma.