title: Assessment of SHOX2 methylation in EBUS-TBNA specimen improves accuracy in lung cancer staging.
abstract: BACKGROUND
  Endobronchial ultrasound with transbronchial needle aspiration (EBUS-TBNA) is a well-established method to assess mediastinal lymph nodes for lung cancer. However, a proportion of patients require further investigation, due to the low negative predictive value (NPV). The objective of this study was to determine whether the assessment of short stature homeobox 2 (SHOX2) DNA methylation level in lymph node tissue obtained by EBUS-TBNA improves the accuracy of mediastinal staging.
  
  
  METHODS
  EBUS-TBNA was carried out for suspicious lymph nodes of 154 patients. Negative or ambiguous histological results were confirmed by surgical means and clinical follow-up over 6 months. EBUS-TBNA was assessed on 80 positive and 85 negative classified lymph nodes and compared with the result of the SHOX2 DNA methylation real-time PCR analysis. Relative methylation measured by delta-delta cycle threshold (ΔΔCt) was used to classify the samples. Clinical performance of the EBUS-TBNA procedure with and without the additional SHOX2 assessment was calculated against the final classification according to the gold standard.
  
  
  RESULTS
  Based on data from 105 patients, an average 80-fold increase in the SHOX2 methylation level was measured for positive compared with negative lymph nodes. SHOX2 results with a ΔΔCt value of <6.5 indicate positive lymph nodes. Applying this molecular analysis to EBUS-TBNA cases, not diagnosed by pathologic assessment, the sensitivity of staging was improved by 17%-99%. The NPV increased from 80% to 99%.
  
  
  CONCLUSIONS
  The combination of EBUS-TBNA and SHOX2 methylation level strongly improves the assessment of the nodal status by identifying additional malignant lesions and confirming benign nodes and therefore avoiding invasive follow-up procedures.
authors.affiliation: Department of Interventional Pneumology, Ruhrlandklinik, University Hospital Essen, University of Duisburg-Essen, Essen, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Darwiche
authors.forename: P
authors.initials: P
authors.lastname: Zarogoulidis
authors.forename: K
authors.initials: K
authors.lastname: Baehner
authors.forename: S
authors.initials: S
authors.lastname: Welter
authors.forename: R
authors.initials: R
authors.lastname: Tetzner
authors.forename: J
authors.initials: J
authors.lastname: Wohlschlaeger
authors.forename: D
authors.initials: D
authors.lastname: Theegarten
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: L
authors.initials: L
authors.lastname: Freitag
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020680:Bronchoscopes; D019175:DNA Methylation / Q000235:genetics; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration; D005260:Female; D005500:Follow-Up Studies; D018398:Homeodomain Proteins / Q000235:genetics*; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging
chemical_list: D018398:Homeodomain Proteins; C484664:SHOX2 protein, human
keywords: DNA methylation; SHOX2; lung cancer