The intestinal microbiota are associated with several of the hallmarks of cancer.

In mathematical biology, there seems to be not much connection between oncological modeling on one side and bacterial population and resource dynamics models on the other hand. In my research group we have developed gut (reactor) models on-and-off for more than 10 years. In this talk I will pose the question whether there is role to play for such models in mathematical oncology. To this end I will give an overview over our gut model that has been derived from the Anaerobic Digestion Model No.1 of the International Water Association, a quasi industry standard in wastewater treatment modeling. I will show a simple application of this model and discuss an extension of a submodel to include competition between mucin degraders such as {\it Bacteroides thetaiotaomicron} and {\it Akkermansia muciniphilia}, both of which have been reported to play a role in cancer of the lower intestinal tract. This is a talk largely without results, based on joint work with Thulasi Jegatheesan and Arun Moorthy.