Our data found Nanog mRNA had the highest specificity
in lung cancer. We further confirmed the high diagnostic value of Nanog protein levels by IHC, Nanog was overexpressed in lung cancer tissues, but rarely expressed in non-malignant lung tissue. Taken together, these results demonstrate that Nanog mRNA is a potential diagnostic marker for lung cancer. Nanog is a transcription factor that plays an important role in maintaining self-renewal of embryonic stem cells. Current studies have reported that the expression of Nanog was higher in multiple cancerous tissues than in their normal counterparts, including breast cancer , gastric adenocarcinomas , colorectal cancer , gliomas  and ovarian serous cystadenocarcinomas . In this study, we found the expression of Nanog Palbociclib price mRNA in bronchoscopic biopsies of lung cancer patients was significantly higher compared to that in non-cancer patients. Although Nirasawa et al.  have also reported that the expression of Nanog mRNA was higher in surgically resected lung cancer tissues than in non-cancerous tissues, it is not known what cells express Nanog in non-cancerous lung
tissues. Using IHC, we found Nanog was only expressed in metaplastic AZD6244 squamous bronchial epithelium cells in 2 out of 50 non-malignant lung tissues, and was negative in normal airway epithelia. Therefore, Nanog may be a good diagnostic marker for lung cancer. In this study, our results showed that the mRNA levels of Bmi1, CD44 and CD133 were not
significantly different between lung cancer and non-malignant lung tissues. Further analyzed by IHC, we observed that Bmi1, CD44 and CD133 were not only expressed in lung cancers, Bmi1 and CD44 were also abundantly expressed in lung interstitial cells, inflammatory cells and bronchial epithelium cells, and CD133 was diffusely expressed in some normal bronchial epithelium cells and bronchial smooth muscle cells, consistent Thiamet G with previous studies [11, 25, 26]. Hence, Bmi1, CD44 and CD133 are poor diagnostic markers for lung cancer. Likewise, although the expression levels of Sox2 and Msi2 mRNA in lung cancer tissues were significantly higher as compared with non-malignant tissues, we found more than 80% of bronchoscopic biopsy specimens of non-cancer patients were positive for Sox2 and Msi2 mRNA, and all non-malignant tissues were positive for Sox2 and Msi2 protein expression, consistent with previous findings [10, 27, 28]. Therefore, Sox2 and Msi2 have poor diagnostic specificity in lung cancer. It is still controversial whether lung cancer cells express OCT4.