The microbiome as a colorectal cancer screening biomarker (CRCbiome)

Presence of certain bacteria in the gut are strongly associated with colorectal cancer. This project aims to discover gut microbiota biomarkers for colorectal cancer screening.
Last updated: 10/21/2021


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. 

We are investigating interactions between CRC, lifestyle and microbiota to better guide prevention of CRC and increase the biomarker performance.

Project Aims

The overall aim om the CRCbiome study is to discover gut microbiota biomarkers for colorectal cancer screening. To reach the overall aim we have defined the following sub-aims:

  1. Identify associations of the gut microbiome with advanced neoplasia, defined as presence of advanced adenoma or CRC
  2. Examine interactions of the gut microbiome with host factors, diet, lifestyle and medication use on advanced neoplasia risk
  3. Describe modifications of the gut microbiome following removal of precursor lesions of CRC

The project is establishing a cohort including including a biobank with fecal samples and biopsies, lifestyle information and data from national health registries for use in future studies. Read more about the study design and data in the cohort paper. 

Design and infrastructure

The project takes advantage of the established infrastructure in the BCSN-trial, and near 3000 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- and demographics 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 status

The reqruitment of study participants started in September 2017 and is now finished with ta total of 1600 participants. The DNA extraction protocol is finished and we have started analysing the metagenome data.  

Paula Istvan started as an affiliated postdoc in October 2020. She will study the effect of the extra hygienic measures adopted during this current pandemic on the gut microbiota. Einar Birkeland started as a postdoc i March 2020. He will work with the microbiota analyses. Cecilie Bucher-Johannessen  also started started as PhD student in march 2020. She will investigate sex differences in microbiota and CRC and interactions with antibiotic use. Ane Sørlie Kværner started as a postdoc in August 2019. She will be workning with lifestyle and diet analyses.