MSACL 2024 Abstract

Development of Technology for High-throughput and Passive Monitoring for Earlier Detection of Colorectal Cancer Maria Sani (1), Iuliia Tirichenko (2), Daniel Simon (1), Petra Paizs (1), James Alexander (1), James Kinross (3), Eduardo Saiz (4), Zoltan Takats (1), Lauren Ford (1) (1) Department of Metabolism, Digestion and Reproduction, Imperial College London (UK) (2) Department of Mechanical Engineering, Imperial College London (UK) (3) Department of Surgery and Cancer, Imperial College London (UK) (4) Department of Materials, Imperial College London (UK) Lauren Ford, BSc (Hons), PhD (Presenter) Imperial College London >> POSTER (PDF)

Presenter Bio: I am an early career researcher and have a background in materials chemistry, having studied for a PhD between the School of Chemistry and the School of Design at the University of Leeds I have experience in polymer technology, physical adsorption theory and purification. I am interested in using these skills to aid detection of disease using mass spectrometry detection. Since joining Imperial in 2019 I have been working as a post-doctoral research associate in the department of Surgery and Cancer, working on the iEndoscope project. This project utilised ambient ionisation mass spectrometry and allowed me to gain critical experience of ambient MS for early cancer detection.

Introduction
Colorectal cancer (CRC) is the third most common cancer globally. Patients with bowel cancer often have unspecific symptoms such as changes in bowel habits1, which can make diagnosis difficult. Bowel cancer screening is usually performed using Faecal Immunochemical Testing (FIT) which has a good sensitivity for advanced CRC but performs poorer in earlier detection cases.2 Furthermore, there is rising incidence of CRC in younger adults who often will not be included in the CRC population surveillance.3 Herein, we have identified an unmet need to develop smarter testing for detection of colorectal cancer using less invasive and patient friendly approaches. There has been a rising interest in digital health surveillance and integration of technology, including toilet habit monitoring.4

Objective
Herein, it is hypothesised that the surface chemistry of bespoke ceramics can be used to capture metabolite information in urine and faecal samples. By coupling to Laser Desorption – Rapid Evaporative Ionisation Mass Spectrometry (LD-REIMS) high throughput direct sample analysis can be carried out with the long term plan of incorporating into a toilet setting.

Methods
LD-REIMS data was collected on a Waters Xevo QTof G2XS mass spectrometer in the range of 50 to 1200 m/z at a rate of 1 scan/second. An Opotek Q-switched optical parametric oscillator (OPO) laser source set to a wavelength of 2940 nm was used for sample ablation. 24 Ceramic materials with differing hydrophobicity, porosity and pore size were tested for their coupling capability with LD-REIMS. Splash LipidoMix mass spectrometry standard (Avanti Lipids) was used as an internal standard spiked into urine for feasibility analysis. Spiked samples were applied to ceramic surfaces (100uL) and washed with water, ammonium acetate (aa) or acidified aa. Faecal samples were collected from the colorectal cancer clinics at Imperial College Healthcare Trust (ICHT) hospital sites (REC: 14/EE/0024). In total 10 CRC, 8 Adenoma and 15 healthy stool samples were collected. Faecal samples were applied to ceramics and washed. In house Peak Picking was performed using in house scripts in R and Matlab. Statistical analysis was performed using Python Jupyter Notebook.

Results
Urine spiked with deuterated standards (Splash Lipidomix), LipidoMix contains 14 standards of deuterium labelled phospholipids, lysolipids, triacylglygerides, diacylglycerides and cholesterol, providing a good coverage of lipid species for analysis. Application of spiked biofluid solutions to ceramic surfaces resulted in an increased recovery of observed lipids. Overall CeO2 ceramic with a porosity of 38.4% and ZrB2 with a porosity of 22.0% resulted in the highest relative abundance of deuterated lipids detected within urine when washed with ammonium acetate solution (150mM, 100uL). Pooled faecal samples were applied to the ceramic surfaces and analysed by LD-REIMS these were compared to native faecal sample aerosolised directly without application to ceramics. For the application of faecal samples to ceramics ZrB2 performed most optimally. Individual faecal samples were also analysed after application to ceramic surfaces, support vector machine learning (SVM) models were built and leave one patient out cross validation (LOPO-CV) done to reveal clinical benchmark performance indicators such as Diagnostic Accuracy (81%), Sensitivity (76%) and Specificity (87%). Scanning Electron Microscopy (SEM) also revealed cell adhesion to ceramic surfaces.

Conclusion
The use of ceramic surfaces with specific porosity resulted in increased sensitivity of interesting features in complex biofluids. It is hypothesised that this increase in sensitivity is due to the specific cavity sizes of the ceramics and the hydrophobic surface chemistry enabling adhesion to the surface whilst salts from the biofluid matrix can be washed away reducing the ion suppression observed in this high throughput analysis. This increased sensitivity resulted in good diagnostic accuracy between Healthy, Adenoma and CRC patients showing promise for a passive testing capability. In adenoma and cancer patient cohorts, tentative annotation using metabolite databases revealed increased relative abundance of oxidised ceramides, oxidised fatty acids, and diacylglycerides are observed.

References
1. D’souza, N., Georgiou Delisle, T., Chen, M., Benton, S. & Abulafi, M. Faecal immunochemical test is superior to symptoms in predicting pathology in patients with suspected colorectal cancer symptoms referred on a 2WW pathway: A diagnostic accuracy study. Gut 70, 1130–1138 (2021).
2. Niedermaier, T., Weigl, K., Hoffmeister, M. & Brenner, H. Diagnostic performance of flexible sigmoidoscopy combined with fecal immunochemical test in colorectal cancer screening: meta-analysis and modeling. Eur J Epidemiol 32, 481–493 (2017).
3. Vuik, F. E. R. et al. Increasing incidence of colorectal cancer in young adults in Europe over the last 25 years. Gut (2019) doi:10.1136/gutjnl-2018-317592.
4. Park, S. min et al. A mountable toilet system for personalized health monitoring via the analysis of excreta. Nat Biomed Eng 4, 624–635 (2020).