Another surface marker, CD44, has also been used to isolate CSC from lung cancer [11]. A previous study using competitive RT-PCR to detect the expression of CD44

in urine for bladder cancer diagnosis was highly accurate and a potential non-invasive diagnostic marker for bladder cancer [12]. Transcription factors, Sox2, OCT4 and Nanog form a core regulatory network of self-renewal and differentiation in embryonic stem cells, which are essential in sustaining stem cell pluripotency [13]. Recent reports show that Sox2, OCT4 and Nanog are potential diagnostic markers for lung cancer [14–16]. Additionally, Musashi2 (Msi2), a RNA binding protein, play crucial roles in maintaining self-renewal and pluriopentency of embryonic stem cells. It have been demonstrated to participate in tumorigenesis and progression of multiple solid tumors [17, 18], and are expressed in lung cancer see more [10]. However, these studies which are mainly based on surgical specimens to screen for new molecular markers have certain limitations in clinical application because most lung cancers are unresectable. Bronchoscopy has become an essential method by which to analyze and diagnose lung cancer through technological advances

and its widespread application. Common bronchoscopy techniques including forceps biopsy, brushing and washing can easily obtained adequate specimens for histological, GS-1101 purchase cytological and

molecular biological analysis [19]. The purpose of this study is to investigate the differential and clinical significance of these stem-cell-associated markers in bronchoscopy biopsy specimens. In this study, we applied RT-PCR Benzatropine to examine the differential expression of Bmi1, CD133, CD44, Sox2, Nanog, OCT4 and Msi2 mRNA in bronchoscopic biopsy specimens from lung cancer and non-cancer patients. Furthermore immunohistochemistry was used to define the localization and expression patterns of these stem-cell-associated proteins in surgically resected lung cancer and non-malignant lung tissues. The diagnostic value of these seven stem-cell-associated markers was evaluated in lung cancer. Materials and methods Clinical samples from bronchoscope biopsy This prospective study in 112 patients with histologically proven lung cancer and 18 non-cancer patients was performed at Guilin Medical University Hospital and Affiliated Nan Xi Shan Hospital in China from January, 2011 to January, 2012. These 112 lung cancer patients included 94 males and 18 females ranging from 29 to 80 years of age (median = 59.2). Fifty-six cases were squamous cell carcinomas (SCC), 17 cases adenocarcinomas (Ad), 28 cases small cell lung carcinomas (SCLC) and 11 cases of other types of lung cancer.