Last updated: 2019.11.15
Background
Colorectal cancer (CRC) symptoms are unspecific - often emerging when the disease is no longer curable. Screening reduces CRC mortality, but current screening tests need improvment to be more accurate and less costly and invasive.
Presence of certain bacteria in the gut are strongly associated with CRC. It is now possible to investigate all bacteria in the gut, - the microbiota, for its role in initiation and progression of colorectal cancer in large epidemiological studies and hence discover disease biomarkers.
Colorectal cancer is one of the cancer types with strongest association with lifestyle, and there is reason to believe that this association is partly mediated trough the gut microbiota.
This project is a sub-study within the Bowel Cancer Screening in Norway (BCSN) trial that aims to discover gut microbiota biomarkers for colorectal cancer screening. We will also investigate interactions between CRC, lifestyle and microbiota to better guide prevention of CRC and increase the biomarker performance.
Project Aims
1. Identify associations between the gut microbiota and cancer precursors/early cancer in a Norwegian screening population
2. Evaluate how the microbiota are modified by removal of adenomas
3. Assess interactions between cancer precursors/early cancer, lifestyle and the gut microbiota. Biomarkers of primary interest are i) gut microbial composition and diversity, and ii) microbial genes and pathways. Lifestyle factors of primary interest are i) body size, ii) smoking, iii) diet and iv) fecal biomarkers for dietary whole grain.
A secondary aim is to establish a sub-cohort within the BCSN with fecal samples, biopsies and lifestyle information for use in biomarker discovery.
Design and infrastructure
The project takes advantage of the established infrastructure in the
BCSN-trial, and 2000 screening participants with a positive Fecal immunochemical (FIT) test will be invited to participate in our study. Before the colonoscopy, we will ask the study participant to fill in a lifestyle questionnaire and a validated food frequency questionnaire, developed at the University of Oslo. Two and twelve months after the colonoscopy, we will ask the participants for a new FIT test, to analyse the microbiota.
Project progression
The reqruitment of study participants started in September 2017 and is ongoing and we have now invited more than half of the participants. The DNA extraction protocol is finished and we have started a pilot of the metagenome analyses.
Even Sannes Riiser started as postdoc in March 2019. He will be workning with the microbiota analyses. Ane Sørlie Kværner started as a postdoc in August. She will be workning with lifestyle and diet analyses.
Collaborators
Ole Herman Ambur, Associate Professor, Oslo and Akershus University College of Applied Sciences.
Robert Lyle, Core Facility Leader/Senior Scientist, Norwegian Sequencing Centre.
Richard Landberg, Professor, Chalmers University of Technology, Gothenburg, Sweden.
Willem de Vos, Professor, University of Helsinki og Professor Wageningen University
Anette Hjartåker, Professor, University of Oslo.
Scott Bultman, Associate Professor, University of North Carolina at Chapel Hill
Vahid Bemanian, Senior engineer/researcher, Akershus University Hospital
Pekka Ellonen, Technology lab at FIMM, Helsinki, Finland
Mingyang Song, Ass. Prof, Harvard T.H. Chan School of Public Health.
