NKI researchers are better mapping the complex relationship between bacteria and tumor cells

Bacteria and cancer cells often appear to have special relationships. Researchers from the Netherlands Cancer Institute (NKI) led by Emile Voest and Lodewyk Wessels have analyzed 4,000 tumors to map which bacteria live in metastases. With this knowledge they hope to find new ways to treat cancer. The study by the NKI scientists has been published in a scientific journal Cell.

Microbiome

It has been known for some time that bacteria play a role in the development but also in the treatment of cancer. The human body’s microbiomes contain billions of microorganisms. This not only concerns the intestinal microbiome (the intestinal flora), but also that of the skin and other places. It has already been established that the microbiome can influence the effectiveness of immunotherapy and chemotherapy.

However, tumors also appear to have their own microbiome. The NKI researchers mainly investigated which bacteria are present in metastases and what their effect on the tumor could be. The researchers analyzed the code of the DNA present in tissue from more than 4,000 metastases from 26 cancer types, both human and bacterial. They used clinical information and DNA data collected by the Hartwig Medical Foundation.

The researchers discovered that not only metastases from colon cancer contain many bacteria. This does not concern bacteria that have traveled from the tumors in the intestine to elsewhere in the body. The bacteria in a metastasis appear to be strongly related to the location in the body, the conditions there and the cancer type.

Effect on therapy

They also discovered a link between bacteria and the effect of therapy. Patients with non-small cell lung cancer and many Fusobacterium in their metastasis, for example, responded worse to immunotherapy than fellow sufferers without that bacteria. In addition, a link was seen between tumor activity and variation in bacterial composition.

The authors believe that their findings open the door to new forms of treatment, for example against bacteria that may help the tumor, thus weakening the tumor and making it vulnerable to immunotherapy.

Reference

Battaglia TW, Mimpen IL, Traets JJH, et al. A pan-cancer analysis of the microbiome in metastatic cancer. Cell. 2024 Apr 25;187(9):2324-2335.e19. doi: 10.1016/j.cell.2024.03.021. Epub 2024 Apr 9. PMID: 38599211.