title: mRNA and miRNA analyses in cytologically positive endobronchial ultrasound-guided transbronchial needle aspiration: implications for molecular staging in lung cancer patients.
abstract: BACKGROUND
  Lung cancer is highly aggressive and tends to metastasize early. Therefore, accurate mediastinal staging is important for therapeutic decision making. Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) has emerged as a minimally invasive procedure for mediastinal lymph node sampling and cancer staging. Classical EBUS-TBNA cytology has been combined with molecular staging techniques to improve sensitivity and specificity. This study aimed to assess mRNA integrity in samples acquired by EBUS-TBNA in the clinics. As proof-of-principle experiments, we also investigated whether stable miRNA could be detected in these samples.
  
  
  METHODS
  Integrity of mRNA isolated from tumor-positive EBUS-TBNA samples was assessed by calculating the RNA integrity number (RIN). In addition, 4 microRNAs were investigated (miRNA 21, miRNA 155, miRNA 200c, and miRNA 34a) because their relation to lung cancer has been documented recently. A group of patients with benign mediastinal lymphadenopathy served as a control.
  
  
  RESULTS
  mRNA isolated from EBUS-TBNA samples was nearly completely degraded if handled under clinical conditions (RIN <5). Intact miRNA was detected in all samples, with no nonspecific amplification in negative control samples. miRNA 21 and miRNA 200c levels were significantly higher in tumor-positive than in control samples (miRNA 21: median, 325,678 [range, 34,822-583,502] vs. 801,430 (range, 17,013-5,362,145]; P < .05; miRNA 200c: median, 9,198 [range, 610-211,121] vs. 42,870 [range, 0-926,252]; P < .05).
  
  
  CONCLUSIONS
  Under clinical conditions, mRNA detection is likely unsuitable for improving sensitivity of EBUS-TBNA-facilitated cancer staging. In contrast, detection of miRNA combined with EBUS-TBNA cytology may improve staging sensitivity.
authors.affiliation: Department of Thoracic Surgery, Lung Clinic Merheim, University Medical Center Witten/Herdecke, Köln, Germany.
authors.forename: Till
authors.initials: T
authors.lastname: Plönes
authors.forename: Mirjam
authors.initials: M
authors.lastname: Elze
authors.forename: Gian
authors.initials: G
authors.lastname: Kayser
authors.forename: Dietmar
authors.initials: D
authors.lastname: Pfeifer
authors.forename: Meike
authors.initials: M
authors.lastname: Burger
authors.forename: Gernot
authors.initials: G
authors.lastname: Zissel
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D044963:Biopsy, Fine-Needle / Q000379:methods; D001999:Bronchoscopy / Q000379:methods; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000473:pathology; D016022:Case-Control Studies; D019160:Endosonography / Q000379:methods*; D005260:Female; D006801:Humans; D061705:Image-Guided Biopsy; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology*; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D035683:MicroRNAs / Q000032:analysis* / Q000235:genetics; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology; D009367:Neoplasm Staging; D011446:Prospective Studies; D012333:RNA, Messenger / Q000032:analysis* / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012016:Reference Values; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D014408:Biomarkers, Tumor; D035683:MicroRNAs; D012333:RNA, Messenger
keywords: EBUS-TBNA; RNA integrity number (RIN); biomarker; epigenetic; lobectomy; microRNA; outcome; survival