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J Clin Pathol 67:707-711 doi:10.1136/jclinpath-2014-202414
  • Original article

Combined sputum hypermethylation and eNose analysis for lung cancer diagnosis

  1. Erik Thunnissen1
  1. 1Department of Pathology, VU University Medical Center, Amsterdam, The Netherlands
  2. 2Department of Respiratory Medicine, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
  3. 3Department of Epidemiology and Biostatistics, VU University Medical Center, Amsterdam, The Netherlands
  4. 4Department of Clinical Epidemiology and Biostatistics, Academic Medical Center, Amsterdam, The Netherlands
  5. 5Department of Pulmonary Diseases, VU University Medical Center, Amsterdam, The Netherlands
  1. Correspondence to Dr Erik Thunnissen, Department of Pathology, VU University Medical Center, De Boelelaan 1117, Amsterdam 1081 HV, The Netherlands; e.thunnissen{at}vumc.nl
  • Received 8 May 2014
  • Accepted 23 May 2014
  • Published Online First 10 June 2014

Abstract

Aims The aim of this study is to explore DNA hypermethylation analysis in sputum and exhaled breath analysis for their complementary, non-invasive diagnostic capacity in lung cancer.

Methods Sputum samples and exhaled breath were prospectively collected from 20 lung cancer patients and 31 COPD controls (Set 1). An additional 18 lung cancer patients and 8 controls only collected exhaled breath as validation set (Set 2). DNA hypermethylation of biomarkers RASSF1A, cytoglobin, APC, FAM19A4, PHACTR3, 3OST2 and PRDM14 was considered, and breathprints from exhaled breath samples were created using an electronic nose (eNose).

Results Both DNA hypermethylation markers in sputum and eNose were independently able to distinguish lung cancer patients from controls. The combination of RASSF1A and 3OST2 hypermethylation had a sensitivity of 85% with a specificity of 74%. eNose had a sensitivity of 80% with a specificity of 48%. Sensitivity for lung cancer diagnosis increased to 100%, when RASSF1A hypermethylation was combined with eNose, with specificity of 42%. Both methods showed to be complementary to each other (p≤0.011). eNose results were reproducible in Set 2.

Conclusions When used in concert, RASSF1A hypermethylation in sputum and exhaled breath analysis are complementary for lung cancer diagnosis, with 100% sensitivity in this series. This finding should be further validated.