title: EBUS-TBNA provides highest RNA yield for multiple biomarker testing from routinely obtained small biopsies in non-small cell lung cancer patients - a comparative study of three different minimal invasive sampling methods.
abstract: BACKGROUND
  Multiple biomarker testing is necessary to facilitate individualized treatment of lung cancer patients. More than 80% of lung cancers are diagnosed based on very small tumor samples. Often there is not enough tissue for molecular analysis. We compared three minimal invasive sampling methods with respect to RNA quantity for molecular testing.
  
  
  METHODS
  106 small biopsies were prospectively collected by three different methods forceps biopsy, endobronchial ultrasound (EBUS) guided transbronchial needle aspiration (TBNA), and CT-guided core biopsy. Samples were split into two halves. One part was formalin fixed and paraffin embedded for standard pathological evaluation. The other part was put in RNA later for immediate RNA/DNA extraction. If the pathologist confirmed the diagnosis of non-small cell lung cancer(NSCLC), the following molecular markers were tested: EGFR mutation, ERCC1, RRM1 and BRCA1.
  
  
  RESULTS
  Overall, RNA-extraction was possible in 101 out of 106 patients (95.3%). We found 49% adenocarcinomas, 38% squamouscarcinomas, and 14% non-otherwise-specified(NOS). The highest RNA yield came from endobronchial ultrasound guided needle aspiration, which was significantly higher than bronchoscopy (37.74 ± 41.09 vs. 13.74 ± 15.53 ng respectively, P = 0.005) and numerically higher than CT-core biopsy (37.74 ± 41.09 vs. 28.72 ± 44.27 ng respectively, P = 0.244). EGFR mutation testing was feasible in 100% of evaluable patients and its incidence was 40.8%, 7.9% and 14.3% in adenocarcinomas, squamouscarcinomas and NSCLC NOS subgroup respectively. There was no difference in the feasibility of molecular testing between the three sampling methods with feasibility rates for ERCC1, RRM1 and BRCA1 of 91%, 87% and 81% respectively.
  
  
  CONCLUSIONS
  All three methods can provide sufficient tumor material for multiple biomarkers testing from routinely obtained small biopsies in lung cancer patients. In our study EBUS guided needle aspiration provided the highest amount of tumor RNA compared to bronchoscopy or CT guided core biopsy. Thus EBUS should be considered as an acceptable option for tissue acquisition for molecular testing.
authors.affiliation: Department of Surgery, University Medical Center Mannheim, Medical Faculty Mannheim of Heidelberg University, Mannheim, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Schmid-Bindert
authors.forename: Yongsheng
authors.initials: Y
authors.lastname: Wang
authors.forename: Hongbin
authors.initials: H
authors.lastname: Jiang
authors.forename: Hui
authors.initials: H
authors.lastname: Sun
authors.forename: Thomas
authors.initials: T
authors.lastname: Henzler
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Lothar R
authors.initials: LR
authors.lastname: Pilz
authors.forename: Shengxiang
authors.initials: S
authors.lastname: Ren
authors.forename: Caicun
authors.initials: C
authors.lastname: Zhou
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics / Q000473:pathology / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D019313:BRCA1 Protein / Q000235:genetics; D014408:Biomarkers, Tumor / Q000235:genetics*; D018196:Carcinoma, Adenosquamous / Q000235:genetics / Q000473:pathology / Q000601:surgery; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D004268:DNA-Binding Proteins / Q000235:genetics; D004720:Endonucleases / Q000235:genetics; D061765:Endoscopic Ultrasound-Guided Fine Needle Aspiration; D019160:Endosonography; D066246:ErbB Receptors / Q000235:genetics; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics* / Q000473:pathology / Q000601:surgery; D008297:Male; D009154:Mutation / Q000235:genetics; D009367:Neoplasm Staging; D011446:Prospective Studies; D012333:RNA, Messenger / Q000235:genetics*; D012334:RNA, Neoplasm / Q000235:genetics*; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012262:Ribonucleoside Diphosphate Reductase; D025521:Tumor Suppressor Proteins / Q000235:genetics
chemical_list: D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D012333:RNA, Messenger; D012334:RNA, Neoplasm; D025521:Tumor Suppressor Proteins; C475286:RRM1 protein, human; D012262:Ribonucleoside Diphosphate Reductase; C512478:EGFR protein, human; D066246:ErbB Receptors; C071447:ERCC1 protein, human; D004720:Endonucleases