Application of a classifier combining bronchial genomics and chest CT features facilitates the diagnostic evaluation of lung cancer in smokers and non-smokers
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ABSTRACT: Introduction: Lung cancer screening by computed tomography (CT) reduces mortality but exhibited high false-positive rates. We established a diagnostic classifier combining chest CT features with bronchial genomics. Materials and Methods: Patients with CT-detected suspected lung cancer were enrolled. The sample collected by bronchial brushing was used for RNA sequencing. R software was applied to build the model. Results: A total of 283 patients, including 183 with lung cancer and 100 with benign lesions, were included. When incorporating genomic data with radiological characteristics, the advanced model yielded 0.903 AUC with 81.1% NPV. Moreover, the classifier performed well regardless of lesion size, location, stage, histologic type, or smoking status. Pathway analysis showed enhanced epithelial differentiation, tumor metastasis, and impaired immunity were predominant in smokers with cancer, whereas tumorigenesis played a central role in non-smokers with cancer. Apoptosis and oxidative stress contributed critically in metastatic lung cancer; by contrast, immune dysfunction was pivotal in locally advanced lung cancer. Conclusions: We devised a minimal-to-noninvasive, efficient diagnostic classifier for smokers and non-smokers with lung cancer, which provides evidence for different mechanisms of cancer development and metastasis associated with smoking. A negative classifier result will help the physician make conservative diagnostic decisions.
Project description:Prior microarray studies of smokers at high risk for lung cancer have demonstrated that heterogeneity in bronchial airway epithelial cell gene expression response to smoking can serve as an early diagnostic biomarker for lung cancer. This study examines the relationship between gene expression variation and genetic variation in a central molecular pathway (NRF2-mediated antioxidant response) associated with smoking exposure and lung cancer. We assessed global gene expression in histologically normal airway epithelial cells obtained at bronchoscopy from smokers who developed lung cancer (SC, n=20), smokers without lung cancer (SNC, n=24), and never smokers (NS, n=8). Functional enrichment showed that the NRF2-mediated antioxidant response pathway differed significantly among these groups. Keywords: Global mRNA expression profiling 21 total arrays (20 unique patients) run on total RNA obtained from Bronchial Epithelium of Smokers with Lung Cancer 30 total arrays (24 unique patients) run on total RNA obtained from Bronchial Epithelium of Smokers without Lung Cancer 9 total arrays (8 unique patients) run on total RNA obtained from Bronchial Epithelium of Never Smokers
Project description:Prior microarray studies of smokers at high risk for lung cancer have demonstrated that heterogeneity in bronchial airway epithelial cell gene expression response to smoking can serve as an early diagnostic biomarker for lung cancer. This study examines the relationship between gene expression variation and genetic variation in a central molecular pathway (NRF2-mediated antioxidant response) associated with smoking exposure and lung cancer. We assessed global gene expression in histologically normal airway epithelial cells obtained at bronchoscopy from smokers who developed lung cancer (SC, n=20), smokers without lung cancer (SNC, n=24), and never smokers (NS, n=8). Functional enrichment showed that the NRF2-mediated antioxidant response pathway differed significantly among these groups. Keywords: Global mRNA expression profiling
Project description:Application of a classifier combining bronchial genomics and chest CT features facilitates the diagnostic evaluation of lung cancer in smokers and non-smokers
Project description:RNA was obtained from histologically normal bronchial epithelium of smokers during time of clinical bronchoscopy from relatively accessible airway tissue. Gene expression data from smokers with lung cancer was compared with samples from smokers without lung cancer. This allowed us to generate a diagnostic gene expression profile that could distinguish the two classes. This profile could provide additional clinical benefit in diagnosing cancer amongst smokers with suspect lung cancer. Keywords: Disease state analysis
Project description:Cigarette smoking is the major cause of cancers of the respiratory tract, including non-small cell lung cancer (NSCLC) and head and neck cancer (HNC). In order to better understand carcinogenesis of the lung and upper airways, we have compared the gene expression profiles of tumour-distant, histologically normal bronchial biopsy specimens obtained from current smokers with NSCLC or HNC (SC, considered as a single group), as well as non-smokers (NS) and smokers without cancer (SNC). RNA from a total of 97 biopsies was used for gene expression profiling (Affymetrix HG-U133 Plus 2.0 array). Differentially expressed genes were used to compare NS, SNC, and SC, and functional analysis was carried out using Ingenuity Pathway Analysis (IPA). Smoking-related cancer of the respiratory tract was found to affect the expression of genes encoding xenobiotic biotransformation proteins, as well as proteins associated with crucial inflammation/immunity pathways and other processes that protect the airway from the chemicals in cigarette smoke or contribute to carcinogenesis. Finally, we used the prediction analysis for microarray (PAM) method to identify gene signatures of cigarette smoking and cancer, and uncovered a 15-gene signature that distinguished between SNC and SC with an accuracy of 83%. Thus, gene profiling of histologically normal bronchial biopsy specimens provided insight into cigarette-induced carcinogenesis of the respiratory tract and gene-signatures of cancer in smokers.
Project description:Modification of Gene Expression of the Small Airway Epithelium in Response to Cigarette Smoking The earliest morphologic evidence of changes in the airways associated with chronic cigarette smoking is in the small airways. To help understand how smoking modifies small airway structure and function, we developed a strategy using fiberoptic bronchoscopy and brushing to sample the human small airway (10th-12th order) bronchial epithelium to assess gene expression (HG-133 Plus 2.0 array) in phenotypically normal smokers (n=10, 33 ± 7 pack-yr) compared to matched non-smokers (n=12). Even though the smokers were phenotypically normal, analysis of the small airway epithelium of the smokers compared to the non-smokers demonstrated up- and -down-regulation of genes in multiple categories relevant to the pathogenesis of chronic obstructive lung disease (COPD), including genes coding for cytokines/innate immunity, apoptosis, mucin, response to oxidants and xenobiotics, and general cellular processes. In the context that COPD starts in the small airways, these gene expression changes in the small airway epithelium in phenotypically normal smokers are candidates for the development of therapeutic strategies to prevent the onset of COPD. Keywords: smokers vs non-smokers
Project description:We previously derived and validated a bronchial epithelial gene expression biomarker to detect lung cancer in current and former smokers. Given that bronchial and nasal epithelium gene expression is similarly altered by cigarette smoke exposure, we sought to determine if cancer-associated gene expression might also be detectable in more readily accessible nasal epithelium. Nasal epithelial brushings were prospectively collected from current and former smokers with pulmonary lesions suspicious for lung cancer in the AEGIS-1 (n=375) and AEGIS-2 (n=130) clinical trials and gene expression profiled using microarrays. Using the 375 AEGIS 1 samples, we identified 535 genes that were differentially expressed in the nasal epithelium of patients who were ultimately diagnosed with lung cancer vs. those with benign disease after one year of follow-up (p<0.001). Using bronchial gene expression data from 299 AEGIS-1 patients (including 157 patients with matched nasal and bronchial expression data), we found significantly concordant cancer-associated gene expression differences between the two airway sites (p<0.001). Differentially expressed genes were enriched for genes associated with the regulation of apoptosis, mitotic cell cycle, and immune system signaling. A nasal lung cancer classifier derived in the AEGIS-1 cohort that combined clinical factors and nasal gene expression had significantly higher AUC (0.80) and sensitivity (0.94) over a clinical-factor only model (p<0.05) in independent samples from the AEGIS-2 cohort (n=130). These results suggest that the airway epithelial field of lung cancer-associated injury in current and former smokers extends to the nose and demonstrates the potential of using nasal gene expression as a non-invasive biomarker for the detection of lung cancer.
Project description:Smoking is the leading cause of lung cancer death, although only a small percentage of smokers develop the disease. Cigarette smoke exposure is known to cause a field of injury in cells throughout the respiratory tract, and while these airway epithelial cells are morphologically normal, they can undergo genetic alterations in response to cigarette smoke exposure. We used microarrays to analyze the gene expression of epithelial cells in the extrathoracic epithelium, specifically nasal and buccal epithelium, to see if these cells underwent similar genetic alterations in response to tobacco exposure as seen in bronchial epithelial cells as has been previously reported. Experiment Overall Design: Buccal and nasal epithelial cell samples were collected from healthy current and never smokers. RNA was isolated from these samples and hybridized to Affymetrix microarrays. Gene expression from never smokers was compared to never smoker gene expression from bronchial epithelium as well as expression data from other tissues to determine commonalities in expression patterns in normal extra- and intra-thoracic samples. In addition, gene expression from smokers and nonsmokers was compared in bronchial, nasal, and buccal epithelium to determine similarities in gene expression in these tissues in response to cigarette smoker exposure.
Project description:The earliest morphologic evidence of changes in the airways associated with chronic cigarette smoking is in the small airways. To help understand how smoking modifies small airway structure and function, we developed a strategy using fiberoptic bronchoscopy and brushing to sample the human small airway (10th-12th order) bronchial epithelium to assess gene expression (Affymetrix HG-U133A array) in phenotypically normal smokers (n=6, 24 ± 4 pack-yr) compared to matched non-smokers (n=5). Compared to samples from the large (2nd to 3rd order) bronchi, the small airway samples had a higher proportion of ciliated cells, but less basal, undifferentiated, and secretory cells. The small, but not large, airway samples included Clara cells, a cell found only in the small airway epithelium, and the small, but not the large, airway epithelium expressed genes for the surfactant apoproteins. Despite the fact that the smokers were phenotypically normal, analysis of the small airway epithelium of the smokers compared to the non-smokers demonstrated up- and -down-regulation of genes in multiple categories relevant to the pathogenesis of chronic obstructive lung disease (COPD), including genes coding for cytokines/innate immunity, apoptosis, pro-fibrosis, mucin, responses to oxidants and xenobiotics, antiproteases and general cellular processes. In the context that COPD starts in the small airways, these changes in gene expression in the small airway epithelium in phenotypically normal smokers are candidates for the development of therapeutic strategies to prevent the onset of COPD. Keywords: response to cigarette smoking
Project description:Upregulation of Expression of the Ubiquitin Carboxyl Terminal Hydrolase L1 Gene in Human Airway Epithelium of Cigarette Smokers The microarray data deposited here is from 39 HG-U133 Plus 2.0 GeneChips, from 12 normal non-smokers, 12 phenotypic normal smokers, 9 Early COPD and 6 COPD individuals, all small airways, all small airway. A subset of these samples have been already submitted under GEO Accession Number GSE 4498. These are: 12 non-smokers samples (GSM101095-GSM101106) and 10 smoker samples (GSM101107-GSM101116). These 22 samples that are also in GSE4498 were described in Harvey, B-G; Heguy, A.; Leopold, P.L.; Carolan, B.; Ferris, B. and Crystal R.G. Modification of Gene Expression of the Small Airway Epithelium in Response to Cigarette Smoking. J. Mol. Med (in press). These data are part of a study aimed at understanding how cigarette smoking modifies neuroendocrine cells, in which microarray analysis with TaqMan confirmation was used to assess airway epithelial samples obtained by fiberoptic bronchoscopy from 81 individuals (normal nonsmokers, normal smokers, smokers with early COPD and smokers with established COPD). Of 11 genes considered to be neuroendocrine cell-specific, only ubiquitin C-terminal hydrolase L1(UCHL1), a member of the ubiquitin proteasome pathway, was consistently upregulated in smokers compared to nonsmokers. Up-regulation of UCHL1 at the protein level was observed with immunohistochemistry of bronchial biopsies of smokers compared to nonsmokers. Interestingly, however, while UCHL1 expression was present only in neuroendocrine cells of the airway epithelium in nonsmokers, UCHL1 expression was also expressed in ciliated epithelial cells in smokers, an intriguing observation in light of recent observations that ciliated cells can are capable of transdifferentiating to other airway epithelium. In the context that UCHL1 is involved in the degradation of unwanted, misfolded or damaged proteins within the cell and is overexpressed in >50% of lung cancers, its overexpression in chronic smokers may represent an early event in the complex transformation from normal epithelium to overt malignancy. Keywords: non-smokers vs phenotypic normal smokers, smokers with early COPD, and smokers with COPD