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Cola

Patients with histologically confirmed colorectal cancer (adenocarcinoma)

Patients without colorectal malignant disease according to data obtained in colonoscopy

Average risk population of both genders aged 40-64 at the time of inclusion lacking alarm symptoms for gastrointestinal cancer

Patients with histologically confirmed colorectal cancer (adenocarcinoma) planned for surgical management

Patients with colon polyps that will perform polypectomy

Paired tissue samples will be taken during surgery for CRC. Tissue material from the same patient will be obtained from the cancerous tissue as well as from normal resected material without malignant infiltration. Minimum of 100 mg of each tissue per sample will be obtained. To compare the emission of VOCs in the CRC tissue surgery material to the emissions from normal tissue by GC-MS in a reasonable number of cancer cases.

Identification of specific VOCs in CRC tissue surgery material

Altogether at least 1000 individuals relatively healthy 40-64 years old population-based collected individuals will get recruited. Breath samples will be collected by asking the study subjects to breath into hybrid breath analyser.

To exclude significant colorectal lesions, laboratory-based FIT testing will be offered to the population cohort group for faecal occult blood in faeces. Serum and plasma samples will also be obtained to have them available if additional testing will be required. Individuals with a FIT test value over the cut-off value (\>10 microg/g faeces) will be invited to colonoscopy. The data analysis procedures and classification models will be tested in this general population and cross-checked against FIT and colonoscopy results.

Secondary validation study in general CRC screening settings

Breath sampling will be performed by using a hybrid sensor device and or GC-MS analysis (by collecting breath samples in adsorbent tubes). Strict requirements for subjects will be imposed prior to the breath sampling to standardise the breath sampling and to limit the influence of confounding factors.

Breath sampling for VOC detection

Serum, plasma sampling for group description and stratification.

Blood sample collection

Microbiota testing

Colonoscopy will be used only according to the clinical indications.

Colonoscopy

Marcis Leja, MD, PhD

Linda Mezmale, MD

The aim of this project is to promote the breath volatile marker concept for colorectal cancer (CRC) screening by advancing developing the application of a novel hybrid analyzer for the purpose.

The hybrid analyzer concept is expected to benefit of combining metal-oxide (MOX) and infrared spectrum (IR) sensor acquired data. The current study will be the first globally to address this concept in CRC detection. In addition, traditional methods, in particular, gas chromatography coupled to mass spectrometry (GC-MS) will be used to address the biological relevance of the VOCs emission from cancer tissue and will assist in further advances of the hybrid-sensing approach.

For addressing the aims of the project, four specific research objectives have been set:

1. To identify cancer-related VOCs emitted by the CRC tissue via the comparison of VOCs emitted from cancer tissue with VOCs emitted by non-cancerous tissue (ex vivo surgery material) by GC-MS.
2. To identify the VOCs differentiating human breath from CRC patients and controls (by GC-MS) as well as compare the chemical signature of CRC patients' breath to the chemical signature of cancer tissue.
3. To evaluate the performance of the set of sensors in the hybrid analyzer and the performance of particular sensors for detecting CRC; to develop and validate a mathematical model for CRC detection.
4. To validate the hybrid analyzer in real-life CRC screening settings, i.e. versus the generally accepted CRC screening approach of faecal occult blood detection.
5. To compare faecal microbiome between CRC group and control.

The scientific results to be obtained during the current project are expected to elucidate the origin and metabolism of volatile biomarkers of CRC. This achievement, in turn, will facilitate the implementation of a new screening test based on the newly developed hybrid analyser into medical practice.

Identification of the VOCs patterns by the sensor array for CRC patients when compared to controls. Addressing these objectives will allow an in-depth understanding of the physiological background for exhaled VOCs in CRC patients and facilitate the development of technologies able to identify the disease and its precursors from an exhaled breath sample.

Exhaled air samples being stored in specific adsorbent tubes. Plasma/serum samples for group stratification. Faecal samples for occult blood testing and microbiota analysis. Tissue samples for specific VOCs analysis.

Hybrid-sensor Breath Analysis for Colorectal Cancer Screening

Hybrid-sensor Breath Analysis for Colorectal Cancer Screening (HYCOR)

The role of confounding factors will be addressed to address their role in VOC emission.

Strict requirements for subjects will be imposed prior to the breath sampling to limit the influence of confounding factors. These will include i.a.; overnight fast (min 12h), refraining from smoking at least 2 hours prior to the sampling, refraining from alcohol consumption (1 day before sampling), avoiding excessive physical activity 1 hour prior to testing and refraining of using breath mints/chewing gums on the day of test.

End-tidal portion of exhalation will be collected using buffered, or CO2 controlled sampling. Breath samples will be pre-concentrated using the sorbent tubes and stored at -86℃. An effort will be made to limit the storage time to 2 month. Next, samples will be analysed using GC-MS.

The characteristic VOC pattern based on sensor analysis and its performance indicators will be detected.

Identification of specific chemistries (GC-MS analysis) originating from colorectal cancer. Volatiles will be separated using an Rt-Q-BOND column working in a constant flow of helium. The column temperature program will be optimized toward detection of observed volatiles. The SCAN, will be used for the untargeted analysis and identification of compounds of breath samples as well as for the quantification of more abundant species. Peak integration will be based on extracted ion chromatograms. The identification of compounds will be performed in two steps. The peak spectrum will be checked against the NIST mass spectral library. The NIST identification will be confirmed by comparing the respective retention times with retention times obtained on the basis of standard mixtures prepared from pure compounds. Whenever possible the VOC emission will be quantified using calibration mixtures prepared from pure liquid or gaseous substances.

Decision on the optimal set of breath sensors that potentially will be included in a sensor analyser for CRC detection. Comparative analysis between the performance of different sensor performance in target disease identification.

Analysis of the role of faecal microbiota in the origin of VOCs in the exhaled breath.

Spots Global Cancer Trial Database for secondary validation study in general crc screening settings