title: Identification of ENO1 as a potential sputum biomarker for early-stage lung cancer by shotgun proteomics.
abstract: BACKGROUND
  Lung cancer is the leading cancer killer. Early detection will reduce the related deaths. The objective of this study was to identify potential biomarkers for early-stage lung cancer in sputum supernatant.
  
  
  METHODS
  Using shotgun proteomics, we detected changes in protein profiles that were associated with lung cancer by analyzing sputum supernatants from 6 patients with early-stage lung cancer and 5 cancer-free controls. Using western blotting, we validated the proteomic results in 22 lung cancer cases and 22 controls. Using enzyme-linked immunosorbent assay (ELISA), we evaluated the diagnostic performance of the biomarker candidates in an independent set of 35 cases and 36 controls.
  
  
  RESULTS
  Proteomics identified 8 biomarker candidates for lung cancer. Western blotting validation of the candidates showed that enolase 1 (ENO1) displayed a higher expression level in patients with cancer than in cancer-free individuals (P = .015). ELISA revealed that the assessment of ENO1 expression in sputum supernatant had 58.33% sensitivity and 80.00% specificity in distinguishing patients with stage I lung cancer from cancer-free individuals.
  
  
  CONCLUSIONS
  The analysis of protein biomarkers in sputum may provide a potential approach for the early detection of lung cancer. Future validation of all the candidates defined by shotgun proteomics in a large cohort study may help develop additional biomarkers that can be added to ENO1 to provide more diagnostic efficacy for lung cancer.
authors.affiliation: Departments of Pathology, University of Maryland School of Medicine, Baltimore, MD.
authors.forename: Lei
authors.initials: L
authors.lastname: Yu
authors.affiliation: Departments of Pathology, University of Maryland School of Medicine, Baltimore, MD.
authors.forename: Jun
authors.initials: J
authors.lastname: Shen
authors.affiliation: Departments of Pathology, University of Maryland School of Medicine, Baltimore, MD.
authors.forename: Kaiissar
authors.initials: K
authors.lastname: Mannoor
authors.affiliation: Departments of Pathology, University of Maryland School of Medicine, Baltimore, MD.
authors.forename: Maria
authors.initials: M
authors.lastname: Guarnera
authors.affiliation: Departments of Pathology, University of Maryland School of Medicine, Baltimore, MD.
authors.forename: Feng
authors.initials: F
authors.lastname: Jiang
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D015153:Blotting, Western; D016022:Case-Control Studies; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology*; D008297:Male; D009367:Neoplasm Staging; D010751:Phosphopyruvate Hydratase / Q000235:genetics* / Q000378:metabolism; D040901:Proteomics / Q000379:methods*; D012680:Sensitivity and Specificity; D013183:Sputum / Q000378:metabolism*; D025521:Tumor Suppressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D025521:Tumor Suppressor Proteins; C095157:ENO1 protein, human; D010751:Phosphopyruvate Hydratase
keywords: Biomarker; ENO1; Lung cancer; Proteomics; Sputum