Sensors and Actuators B 202 (2014) 615–621 Contents lists available at ScienceDirect Sensors and Actuators B: Chemical jo ur nal home page: www.elsevier.com/locate/snb Determination of volatile organic compounds as potential markers of lung cancer by gas chromatography–mass spectrometry versus trained dogs Joanna Rudnicka a , Marta Walczak b , Tomasz Kowalkowski a , Tadeusz Jezierski b , Bogusław Buszewski a,∗ a Department of Environmental Chemistry and Bioanalytics, Faculty of Chemistry, Nicolaus Copernicus University, 7 Gagarin St, 87-100 Toru´ n, Poland b Institute of Genetics and Animal Breeding of Polish Academy of Sciences, Department of Animal Behaviour, Post˛ epu 36A, Jastrz˛ ebiec, 05-552 Magdalenka, Poland a r t i c l e i n f o Article history: Received 23 January 2014 Received in revised form 22 April 2014 Accepted 3 June 2014 Available online 7 June 2014 Keywords: Lung cancer Volatile organic compounds Solid phase microextraction Gas chromatography–mass spectrometry Canine olfactory a b s t r a c t The main aim of the study was qualitative and quantitative analysis of volatile organic compounds (VOCs) occurring in biological samples such as exhaled air obtained from 108 patients with lung cancer, 121 healthy volunteers, and 24 persons with other lung diseases. For determination of VOCs in human breath, solid phase microextraction and gas chromatography–mass spectrometry (SPME/GC–MS) were applied. Statistical methods such as artificial neural network and chi-squared automatic interaction detector (CHAID) were applied for data evaluation. The concentration of acetone, isoprene, ethanol, 1-propanol, 2-propanol, hexanal, and dimethyl sulfide were higher in patients with lung cancer than in case of healthy volunteers and persons with other lung diseases. The second goal was the application of trained dogs for detection of the same breath samples as in GC–MS research and evaluate the sensitivity and specificity of canine scent detection using 5 station scent lineup. Among lung cancer patients and complementary samples, overall sensitivity of canine scent detection was 86%, while specificity was 72%. There is a possibility that in the future these methods could allow for a fast, painless, and noninvasive diagnosis of cancer. © 2014 Elsevier B.V. All rights reserved. 1. Introduction Morbidity and mortality caused by cancer diseases seem to be the most important health problem in modern society. The most common cancer in the world is lung cancer with 1.6 million new cases diagnosed every year [1]. Medical progress involved is huge, however, cancer therapy is not perfect; so early cancer detection is a desirable goal as it often allows treatment with a lower toxicity and can lead to longer survival [2,3]. Screening tests are based par- ticularly on imaging such as X-radiation (X-ray), ultrasonography (USG), computed tomography (CT), and positron emission tomo- graphy (PET); however, these methods have limitations in reliably discriminating between cancer patients and healthy subjects (e.g., some benign masses can look like cancer giving false-positive ∗ Corresponding author. Tel.: +48 566114308; fax: +48 566114837. E-mail addresses: bbusz@chem.umk.pl, bbusz@chem.uni.torun.pl (B. Buszewski). anatomical screens). Existing noninvasive screening methods using proteomic and genetic technologies detecting molecular biomark- ers may be supplemented by innovative methods such as exhaled breath analysis [4]. Odorant molecules such as volatile organic compounds (VOCs) are typically small volatile organic molecules with molecular mass less than 400 Da [5]. Some of the compounds are gener- ated in the human body during metabolic process, e.g., acetone formed by decarboxylation of acetoacetate or acetyl-CoA, high- est concentration of which could be a sign of diabetic disease. Isoprene is produced along the mevalonic pathway of cholesterol synthesis in the cytosolic fraction. It is identified as marker of dis- orders in cholesterol metabolism. Hydrocarbons such as ethane and pentane are produced by lipid peroxidation of polyunsaturated fatty acids. Sulfur-containing compounds such as ethyl mercap- tane, dimethylsulfide, or dimethyldisulfide could be generated by incomplete metabolism of methionine in the transamination path- way. Whereas nitrogen-containing compounds (dimethylamine and trimethylamine) are identified in the breath of patients with http://dx.doi.org/10.1016/j.snb.2014.06.006 0925-4005/© 2014 Elsevier B.V. All rights reserved.