Each year, approximately 12,000 men die of prostate cancer in the United Kingdom (50,000 new cases per year in France, for 8,000 deaths, editor’s note). A recent study published in the journal European Urology Oncology suggests that the origin of this disease could be linked to bacteria. Explanations.
Each year, approximately 12,000 men die of prostate cancer in the United Kingdom (50,000 new cases per year in France, for 8,000 deaths, editor’s note). But they are far more likely to die with prostate cancer than to die from it. It is therefore important to know whether the disease will progress quickly or not in order to know who to treat.
Our latest study, published in European Urology Oncology, provides insight into which cancers will progress rapidly and aggressively and which will not. Part of the explanation for these evolutionary differences lies in five types of bacteria.
It’s a surprise… without being. In recent years, it has indeed been proven that pathogenic microorganisms (bacteria and viruses) can cause cancer. We know, for example, that Helicobacter pylori is associated with stomach cancer and that human papillomavirus (HPV) can cause cervical cancer. There is also growing evidence that the bacterium Fusobacterium nucleatum is associated with colorectal cancer.
Five bacteria identified
Here at Norwich Medical School, together with our colleagues at Norfolk and Norwich University Hospital, the Quadram Institute and others, we have identified five types (genera) of bacteria linked to aggressive prostate cancer. It is Anaerococcus, Peptoniphilus, Porphyromonas, Fenollaria and Fusobacterium. We call them the Anaerobic Bacteria Biomarker Set, or ABBS (anaerobic meaning they can grow in the absence of oxygen).
The genera of bacteria are themselves subdivided into « species », as we ourselves are of the genus Homo and of the species sapiens. And here we found four entirely new bacterial species, three of which belong to the genera associated with aggressive prostate cancer (two of these new species were named after our funders: Porphyromonas bobiiaccording to the Bob Champion Cancer Trust and Varibaculum prostatecancerukia, Prostate Cancer UK).
To find out if they had any particular impact, we looked at urine and prostate tissue samples from more than 600 men with and without prostate cancer. And we found that when any of these five anaerobic bacteria were detected in patient samples, they were associated with faster cancer progression to an aggressive form.
Indeed, men who had one or more of these bacteria were almost three times more likely to see their early-stage cancer progress to advanced disease, compared to those who had none of these microorganisms in their urine or prostate.
We also uncovered the possible mechanisms of the link between these bacteria and cancer, including potential effects on the metabolism of human host cells.
Towards better screening tests
Current prostate cancer screening tests, such as PSA (prostate specific antigen) testing and biopsy, are not always able to predict which cancers will be dangerous.
We hope that a new approach, which would look for the bacteria in our ABBS group, would be better able to detect and screen for potentially aggressive prostate cancer. This new type of test could be similar to those developed to detect Helicobacter pylori associated with stomach cancer or HPV associated with cervical cancer.
We are currently working on it. We plan to develop reliable and rapid tests to detect the five characteristic bacteria that we have identified. They could also help develop new treatment options to clear them from the urinary tract, bladder and prostate.
But this exciting discovery is of course only in its infancy. There are still important questions to be answered, such as: is the bacterium the cause of prostate cancer? If yes, how ? Also, can we use treatment options to eradicate the bacteria to prevent the development of aggressive disease? We hope to have answers to these questions soon.
*This article was written by Rachel HURST, researcher, Colin COOPER professor in genetic oncology, Jeremy CLARK, associate researcher. All work at the University of East Anglia.
The original version of this article was published in The Conversation.
