Tobacco smoking is the leading cause of lung cancer worldwide. Gene expression in surgically resected and microdissected samples of non-small-cell lung cancers (18 squamous cell carcinomas and nine adenocarcinomas), matched normal bronchial epithelium, and peripheral lung tissue from both smokers (n = 22) and non-smokers (n = 5) was studied using the Affymetrix U133A array. A subset of 15 differentially regulated genes was validated by real-time PCR or immunohistochemistry. Hierarchical cluster analysis clearly distinguished between benign and malignant tissue and between squamous cell carcinomas and adenocarcinomas. The bronchial epithelium and adenocarcinomas could be divided into the two subgroups of smokers and non-smokers. By comparison of the gene expression profiles in the bronchial epithelium of non-smokers, smokers, and matched cancer tissues, it was possible to identify a signature of 23 differentially expressed genes, which might reflect early cigarette smoke-induced and cancer-relevant molecular lesions in the central bronchial epithelium of smokers. Ten of these genes are involved in xenobiotic metabolism and redox stress (eg AKR1B10, AKR1C1, and MT1K). One gene is a tumour suppressor gene (HLF); two genes act as oncogenes (FGFR3 and LMO3); two genes are involved in matrix degradation (MMP12 and PTHLH); three genes are related to cell differentiation (SPRR1B, RTN1, and MUC7); and five genes have not been well characterized to date. By comparison of the tobacco-exposed peripheral alveolar lung tissue of smokers with non-smokers and with adenocarcinomas from smokers, it was possible to identify a signature of 27 other differentially expressed genes. These genes are involved in the metabolism of xenobiotics (eg GPX2 and FMO3) and may represent cigarette smoke-induced, cancer-related molecular targets that may be utilized to identify smokers with increased risk for lung cancer.

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Pleural effusions may result from various inflammatory, hemodynamic, or neoplastic conditions. A common diagnostic problem lies in distinguishing malignant from benign pleural effusions using routine cytological evaluation. We studied pleural fluid samples obtained from 14 patients with histologically confirmed malignancy and from 6 patients with benign pleural effusions using 12 microsatellite markers from 8 different chromosomal regions. Supernatants and cellular sediments of all 20 pleural fluid samples were analyzed. Routine cytological examination was 100% specific for malignancy but was only 57% sensitive. Microsatellite analyses of pleural fluid supernatants showed genetic alterations in tumor patients only. However, 50% of pleural effusions that were considered negative for malignancy by routine cytological analysis showed either loss of heterozygosity or microsatellite instability. The sensitivity of pleural fluid examination rose to 79% when routine cytological assessment was supplemented by molecular studies. Our data suggest that microsatellite analysis increases the sensitivity of cytological pleural fluid examination in assessing potential malignancy and that combining cytological and molecular methods may improve yield and certainty in diagnostically challenging cases.

Multitarget fluorescence in situ hybridization (FISH; LAVysion, Vysis, Downers Grove, IL) targeting chromosomes 6p11-q11, 7p12, 8q24, and 5p15.2 was compared with results of microsatellite studies at chromosome 3p to identify molecular changes associated with tobacco use and tumor development in non-small cell lung cancer (NSCLC). Analyses were performed on 26 NSCLCs and matched benign bronchial epithelium; samples from 10 patients without NSCLC served as control samples. Significant molecular differences between tumor tissue and corresponding benign bronchi were found using FISH (P = .001) and loss of heterozygosity (LOH) analysis (P = .031). Bronchial epithelium from patients with NSCLC was genetically different from epithelium from patients without NSCLC in FISH analysis (P = .025). Receiver operating characteristic curve analysis revealed an optimal cutoff value of 5% atypical cells for bronchial epithelium. There was no statistical correlation with the patient's smoking history, and LOH analysis of bronchi did not differentiate between patients with and without NSCLC. Multicolor FISH analysis is able to detect a tumor-associated molecular field effect in bronchi adjacent to NSCLC.

Multitarget fluorescence in situ hybridization (FISH; LAVysion, Vysis, Downers Grove, IL) targeting chromosomes 6p11-q11, 7p12, 8q24, and 5p15.2 was compared with results of microsatellite studies at chromosome 3p to identify molecular changes associated with tobacco use and tumor development in non-small cell lung cancer (NSCLC). Analyses were performed on 26 NSCLCs and matched benign bronchial epithelium; samples from 10 patients without NSCLC served as control samples. Significant molecular differences between tumor tissue and corresponding benign bronchi were found using FISH (P = .001) and loss of heterozygosity (LOH) analysis (P = .031). Bronchial epithelium from patients with NSCLC was genetically different from epithelium from patients without NSCLC in FISH analysis (P = .025). Receiver operating characteristic curve analysis revealed an optimal cutoff value of 5% atypical cells for bronchial epithelium. There was no statistical correlation with the patient's smoking history, and LOH analysis of bronchi did not differentiate between patients with and without NSCLC. Multicolor FISH analysis is able to detect a tumor-associated molecular field effect in bronchi adjacent to NSCLC.