Bmi1 was diffusely expressed in bronchial epithelium cells, alveolar epithelium cells, lung interstitial cells and some inflammatory cells of all non-malignant lung tissues (Figure 2A), and was diffusely expressed in 47 cases of lung cancer and focally expressed in 1 case of Ad and 1 case of SCLC (Figure 2A). This evidence concerns the gene BMI1 and lung cancer.