Diagnosis of Gastric Lesions From Exhaled Breath and Saliva
Condition: Stomach Diseases
MeSH terms: Stomach Diseases
Study type: Observational

Summary: 
      The investigators study the feasibility of a novel method in oncology based on breath
      analysis with a nanosensors array for identifying gastric diseases. Alveolar exhaled breath
      samples collected from volunteers referred for upper endoscopy or surgery are analyzed using
      a custom-designed array of chemical nanosensors based on organically functionalized gold
      nanoparticles and carbon nanotubes. Predictive models are built employing discriminant factor
      analysis (DFA) pattern recognition method. Classification accuracy, sensitivity and
      specificity are determined using leave-one-out cross-validation or an independent blind test
      set. The chemical composition of the breath samples is studied using gas chromatography
      coupled with mass spectrometry (GC-MS).

      A pilot study is conducted first (enlistment of 160 subjects at the Department of Oncology,
      The First Affiliated Hospital of Anhui Medical University, The First Affiliated Hospital of
      Anhui Medical University, Hefei, Anhui, China.)

      The pilot study is followed by a large-scale clinical trial to confirm the preliminary
      results of the Chinese pilot study (enlistment of 800 subjects at the Digestive Diseases
      Centre GASTRO, Riga East University Hospital, 6 Linezera iela, LV1006 Riga, Latvia). 25% of
      the samples are used as independent blind test set. The samples are blinded by the medical
      team and are not disclosed until prediction of blind sample identity is complete.

      To further prove the diagnosis of GC from exhaled breath and seek the interrelationship among
      Breathomics, metabolomics and transcriptomics, saliva samples from about 200 patients are
      collected from volunteers referred for upper endoscopy or surgery are analyzed using
      Ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS). Simultaneously,
      RNA sequencing are preformed on gastric cancer tissue samples and paracancerous tissue
      samples collected from same group of volunteers. The data of salivary metabonomics and
      transcriptomics were integrated and analyzed on the on Kyoto Encyclopedia of Genes and
      Genomes to confirm the diagnostic validity of salivary metabonomics.
    

Detailed description: 
      Number of patients that will have a definitive diagnosis and Alveolar exhaled breath samples
      collected from individuals with Tedlar® bags (Keika Ventures, LLC) after endoscopy.. Two
      breath samples were collected from each person tested.

      Two-bed sorption tubes filled with the following sorbents were used as traps for sample
      collection with simultaneous preconcentration: 100mg matrix Tenax TA and 50mg matrix Tenax TA
      (35-60 mesh; purchased from Supelo, Bellefonte, PA). Sorbents were separated by glass wool.
      The samples were collected at a total flow through sorption trap of 200ml/min.

      One sample was used for analysis with the nanosensors array, and the other sample was used
      for Gas Chromatography coupled with Mass Spectrometry (GC-MS) analysis.

      Cancer tissue and paracancerous tissue samples were collected in the process of surgical
      resection. After collection in the operating room, the samples were immediately placed in - 5
      ℃ dry ice and transferred to the laboratory. Then, the samples were frozen in liquid nitrogen
      for 30 minutes, and then placed in - 80℃ freezer for cold storage. After that, the samples
      were divided into several batches and transported in dry ice for subsequent transcriptome
      analysis. All the saliva samples were collected using 2ml cryopreservation tube during early
      morning before surgery or endoscopic resection. The patient had been told not to eat after 22
      o'clock the night, and not to drink water, smoke, brush teeth or exercise violently one hour
      before the collection. The saliva samples were sealed in the -80 C refrigerator after
      collection and then transported in a foam box equipped with dry ice, followed by UHPLC-MS
      analysis.
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        160 volunteers who undergo gastroscopy examination in The First Affiliated Hospital of
        Anhui Medical University,Hefei,China and 800 patients with dyspeptic symptoms referred for
        upper endoscopy or patients suspected for gastric cancer referred for surgery in the
        clinical sites of University of Latvia (Riga East University hospital and/or Digestive
        Diseases Centre GASTRO), Riga, Latvia
      
Biospecimen description: 
      exhaled breath of volunteers; saliva; tissue
    
Keywords: Oncologic Investigations; Gastric Diseases; Gastric Cancer; Gastric Ulcer; Breath Analysis; Volatile Biomarkers; Nanosensors Array; Discriminant Factor Analysis; GC-MS; Breath Tests; UHPLC; Salivia