Ex-vivo volatilomics profiling of gastric cancer and non-cancerous tissue
Daria Slefarska 1-3*, Linda Mezmale 4, Ilze Kikuste 4,5, Marcis Leja 4-6, Chris A. Mayhew 1,3, Pawel Mochalski 1-3
1. Institute for Breath Research, University of Innsbruck, Dornbirn, Austria, 2. Institute of Chemistry, Jan Kochanowski University, Kielce, Poland, 3. Tiroler Krebsforschungsinstitut (TKFI), Innsbruck, Austria, 4. Institute of Clinical and Preventive Medicine & Faculty of Medicine, University of Latvia, Riga, Latvia, 5. Digestive Diseases Centre GASTRO, Riga, Latvia, 6. Riga East University Hospital, Riga, Latvia
Background The human body releases numerous volatile organic compounds (VOCs) through various body fluids and tissues. These compounds create a specific chemical profile, which may subsequently be employed for the detection of metabolic changes in the human body caused by gastric cancer. A number of recent studies involving various e-noses have provided sufficient evidence that breath analysis can pinpoint novel biomarkers for the diagnosis of this cancer. Unfortunately, the chemical identity of the gastric cancer markers in breath is still unknown. In this context, the emission of VOCs from the tissues of gastric cancer are of importance for aiding in biomarker discovery. Here we identify VOCs emitted from gastric cancer and non-cancerous tissues, and determine differences in this emission. VOCs released by tissue samples were trapped by solid phase microextraction and then analysed using gas chromatography with mass spectrometric detection. A total of 44 patients (32 males and 12 females) were enrolled in the study. Results Sixty-two VOCs were reliably identified through a comparison of peak spectra with the NIST mass spectral library and corresponding retention indices obtained from reference standards. The predominant chemical classes are: ketones, aldehydes, hydrocarbons and heterocyclic compounds. The most ubiquitous compounds are 2-butanone, 2-pentanone, n-pentane, ethyl acetate, isoprene, 2-methyl-2-propanol, butyrolactone, pyrrole and 6-methyl-5-hepten-2-one. Further analyses are required to perform more robust statistical analysis and pinpoint potential markers of gastric cancer.