Trial lecture
“How the gut microbiome may shape colorectal cancer risk and related diagnostic strategies”
Time and place: June 13, 2025 11:15. Kristen Nygaards sal (5370), Ole-Johan Dahls hus.
Main research findings
Our gut is home to trillions of microorganisms—collectively known as the gut microbiome—that play a role in health and disease. Research suggests that changes in the microbiome may be linked to colorectal cancer (CRC) development and that it may serve as an early indicator (a biomarker) for CRC. Current CRC screening methods often lack precision when it comes to CRC detection, highlighting the need for improved screening tools.
This thesis explores the gut microbiome as a source for CRC biomarkers. We demonstrate that healthy individuals, those with early signs of disease (premalignant lesions), and CRC patients have different microbiomes and that these changes are noticeable ~10 years before diagnosis. One bacterium, Phascolarctobacterium succinatutens, was more commonly detected in people with CRC. We further discovered that the Phascolarctobacterium genus comprises three distinct species that form distinct microbial communities. Lastly, we show that men and women have different microbiome profiles, including a higher prevalence of Phascolarctobacterium succinatutens in men. We also demonstrate more variation in the female microbiome, which is related to the severity of colorectal lesions. Overall, we propose Phascolarctobacterium succinatutens as a CRC biomarker candidate and emphasize the importance of considering sex in microbiome biomarker studies.
Adjudication committee
- Professor Marc Gunter, Imperial College London, UK
- Associate Professor Veronika K. Pettersen, University of Tromsø, The arctic University of Norway, Norway
- Associate Professor Pooya Zakeri, University of Oslo, Norway
Supervisors
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Professor Trine Ballestad Rounge, University of Oslo, Norway
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Senior Researcher Paula Berstad, Norwegian Institute of Publich Health
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Professor Emeritus Johannes Eivind Hovig, University of Oslo, Norway
Chair of defence
- Professor Jens Johan Kaasbøll, Department of Informatics, University of Oslo
Contact information at Department: Mozhdeh Sheibani Harat