title: Proteomic study of benign and malignant pleural effusion.
abstract: BACKGROUND
  Lung adenocarcinoma can easily cause malignant pleural effusion which was difficult to discriminate from benign pleural effusion. Now there was no biomarker with high sensitivity and specificity for the malignant pleural effusion.
  
  
  OBJECTIVE
  This study used proteomics technology to acquire and analyze the protein profiles of the benign and malignant pleural effusion, to seek useful protein biomarkers with diagnostic value and to establish the diagnostic model.
  
  
  METHODS
  We chose the weak cationic-exchanger magnetic bead (WCX-MB) to purify peptides in the pleural effusion, used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) to obtain peptide expression profiles from the benign and malignant pleural effusion samples, established and validated the diagnostic model through a genetic algorithm (GA) and finally identified the most promising protein biomarker.
  
  
  RESULTS
  A GA diagnostic model was established with spectra of 3930.9 and 2942.8 m/z in the training set including 25 malignant pleural effusion and 26 benign pleural effusion samples, yielding both 100 % sensitivity and 100 % specificity. The accuracy of diagnostic prediction was validated in the independent testing set with 58 malignant pleural effusion and 34 benign pleural effusion samples. Blind evaluation was as follows: the sensitivity was 89.6 %, specificity 88.2 %, PPV 92.8 %, NPV 83.3 % and accuracy 89.1 % in the independent testing set. The most promising peptide biomarker was identified successfully: Isoform 1 of caspase recruitment domain-containing protein 9 (CARD9), with 3930.9 m/z, was decreased in the malignant pleural effusion.
  
  
  CONCLUSIONS
  This model is suitable to discriminate benign and malignant pleural effusion and CARD9 can be used as a new peptide biomarker.
authors.affiliation: Department of Respiratory Medicine, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, China.
authors.forename: Hongqing
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Respiratory Medicine, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, China.
authors.forename: Zhonghao
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Department of Respiratory Medicine, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, China. zhuhuili001@126.com.
authors.forename: Huili
authors.initials: H
authors.lastname: Zhu
authors.affiliation: Department of Respiratory Medicine, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Ge
authors.affiliation: Department of Respiratory Medicine, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, China.
authors.forename: Shilei
authors.initials: S
authors.lastname: Cui
authors.affiliation: Department of Respiratory Medicine, Huadong Hospital Affiliated to Fudan University, Shanghai, 200040, China.
authors.forename: Weiping
authors.initials: W
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D015415:Biomarkers / Q000737:chemistry / Q000378:metabolism; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000378:metabolism*; D010996:Pleural Effusion / Q000145:classification / Q000378:metabolism*; D040901:Proteomics; D015203:Reproducibility of Results; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D015415:Biomarkers; D009363:Neoplasm Proteins
keywords: Biomarker; Lung adenocarcinoma; Magnetic bead; Malignant pleural effusion; Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry; Proteomic