Cancer Microbiology Group


Research narrative




Guided visualization of high-risk cancer precursor lesions

Sessile serrated lesions (SSLs) are considered precursors for the majority of right-sided CRC, but hard to detect during colonoscopy because of their flat and non-ulcerated nature. It is expected that at least 17% of these precursor lesions are missed during colonoscopy.

Bacterial biofilms are frequently present on right-sided CRC, and in patients with familial adenomatous polyposis coli, and hence biofilms potentially could be a surrogate marker for precursor lesions.

In this project we define whether biofilms occur on conventional adenomas and sessile serrated lesions and whether they can be used to improve detection of high-risk adenomas during colonoscopy.

This project is funded by the Dutch cancer research foundation (KWF) and a personal awarded NWO OffRoad.

Biofilms as risk factor for neoplasia development

In ulcerative colitis (UC) chronic inflammation may lead to the development of mucosal dysplasia that can progress to colitis-associated colorectal cancer (CRC). The altered colonic microbiota has been related to the chronic inflammation in UC, but so far no clear bacterial profile has been associated with an increased risk of colonic neoplasia. The inner mucosal layer of UC patients is frequently covered with bacteria in an adherent polymeric matrix, so-called biofilms. These biofilms may allow migration of bacteria and pro-oncogenic bacterial products.

In this project we aim to identify whether biofilms appear to be a risk factor for neoplasia development in UC. Biofilms could be the missing link between the alterations in colonic microbiota, instigation of chronic inflammation in IBD and pathogenesis of neoplasia.

This project is funded by a personal NWO Veni award and the NVGE.


The metastatic microbiome

Metastasis are the main cause of mortality for colorectal cancer. Increasing evidence shows that intestinal microbiota can effect CRC initiation and progression. However, it is less clear what their influence is on metastasis.

Our main aim is to provide a proof of concept for the functional relevance of either intestinal or hepatic microbiota on the formation and development of CRC liver metastasis. To this end we will compare primary and metastatic tumours form patients, and utilize an orthotopic mouse model for CRC metastasis.

Identifying if and how the microbial component contributes to (liver) metastasis will fill a gap in our knowledge. More importantly, more fully understanding the metastatic process will contribute to new leads for the treatment of metastatic cancer.

This project is funded by the Dutch Cancer research foundation (KWF).


The breast-gut microbiome axis in ER+ breast cancer

Neoadjuvant chemotherapy is effective in only 21% of women with breast cancer. It is therefore important to understand the factors that may influence outcome of neoadjuvant chemotherapy.

The gut microbiome potentially plays a role via the reuptake of hormones from the gut, or by suppressing or stimulating the immune systems that attacks the tumour.

Our aim is to identify the effects of neoadjuvant chemotherapy on the local breast and gut microbiome and how this influences the effectiveness of breast cancer treatment.

This project is funded by the Radboudumc-MUMC alliance fund and is performed in collaboration with Prof. Marjolein Smidts from MUMC.




Our Team

Research technician
Esther Wagena

Esther is a research technician specialized in animal models. She is affiliated at the department of Cell biology. She works with animal models for colon cancer metastasis.

Floor Baas

Floor is a biomedical scientist performing her doctoral thesis in host-microbe interaction studies in 2D-colon organoid models along the adenoma carcinoma sequence.

Research technician
Renske Cremers

Renske has joined our team as research technician in 2022. Her work entails microbial in situ visualization techniques and tissue microbiome analysis.

Joyce Aarts

Joyce is a biomedical scientist. She researches the effects of milk extracellular vesicles on epithelial barrier function in colon organoids in the context of rheumatoid arthritis.

Cheng-Liang Zhou

Cheng-Liang is a medical doctor performing his doctoral thesis on the influence of the gastric and GI microbiome on (hereditary) gastric cancer development.



Prof. dr. Iris Nagtegaal

Iris is a pathologist specialized in gastrointestinal pathology. She is the chair of our research theme and group leader of the colorectal cancer research group.

Prof. dr. Bas Dutilh

Bas is a biofinformatician specialized in metagenomics. We have a long standing collaboration with his metagenomics group and co-supervise multiple PhD-students.

Dr. Daniel Garza

Daniel is a bioinformatician specialized in metabolic models. He obtained his PhD, and worked as postdoc in our group to understand microbiome function in colon cancer.

Dr. Tanya Bisseling

Tanya is a gastroenterologist specialized in hereditary syndromes and colorectal cancer screening, involved in patient inclusion and part of our multidisciplinary team.


Former members

Graduated PhD 2020
Daniel Garza

Daniels PhD-research focussed on the application of genomic scale metabolic models to explore microbial ecology and evolution

Graduated PhD 2022
Rahwa Taddese

Rahwa's PhD- research focused on bacteria enriched in the tumour microenvironment and how they impacted colon epithelial cells.

Graduated PhD 2023
Carlijn Bruggeling

Carlijns PhD-research focussed on colon bacterial biofilms and their role in neoplasia development in patients with the Lynch syndrome and ulcerative colitis.