Research shows this type of mouth bacteria ‘melts’ some forms of cancer
Scientists have discovered that a common type of mouth bacteria can ‘melt’ certain types of cancer.
Researchers from Guy’s and St Thomas’ and King’s College London said they were “brutally surprised” to find that fusobacterium, a type of bacteria commonly found in the mouth, appears to be able to kill certain types of cancer.
A study has found that people with head and neck cancer who have this bacterium found in their cancer have much better prognoses.
Researchers are now investigating the exact biological mechanisms behind this link, following initial findings.
Dr Miguel Reis Ferreira, the lead author of the study and a consultant in head and neck cancers at Guy’s and St Thomas’, told the PA news agency: “Essentially we found that when you find these bacteria in head and neck cancers, they have much better outcomes. The other thing we found is that in cell culture, this bacteria can kill cancer.
“What we’re finding is that this little critter is causing a better outcome based on something it’s doing in the cancer. So we’re looking for that mechanism right now, and it should be the subject of a new paper in the very near future.”
He added: “This research reveals that these bacteria play a more complex role than previously known in their relationship with cancer – that they are essentially melting down head and neck cancer cells. However, this finding should be balanced by their known role in worsening cancers such as those in the bowel.”
Scientists used modeling to help identify which bacteria might be interesting to study further. They then studied the bacteria’s effect on cancer cells in a lab and also analyzed data from 155 head and neck cancer patients whose tumor information had been submitted to the Cancer Genome Atlas database.
Scientists initially expected a different outcome, as previous research had linked Fusobacterium to the progression of colon cancer.
In the lab studies, researchers put samples of the bacteria in petri dishes and let them sit for a few days. When they came back to examine the bacteria’s effect on the cancer, they found that the cancer was nearly gone.
They found that the number of viable cancer cells in head and neck cancer cells decreased by 70%-99% after infection with fusobacterium.
Analysis of patient data showed that those with Fusobacterium in their cancer had better survival rates compared to those who did not. Detecting Fusobacterium in head and neck cancers was associated with a 65% reduction in the risk of death compared to patients whose cancers did not contain the bacteria.
Researchers hope the discovery could contribute to the treatment of patients with head and neck cancer, which includes cancers of the mouth, throat, larynx, nose and sinuses.
According to experts, little progress has been made in the treatment of head and neck cancer in the past 20 years. It is hoped that this discovery could lead to new treatments in the future.
Reis Ferreira said that before the lab work, the team had expected that fusobacterium would encourage these cancers to grow or make them more resistant to radiotherapy. But they found that “after a few days, it just completely destroys the cancer.”
“If you put it into the cancer in very small amounts, it starts killing the cancer very quickly,” he said.
Dr Anjali Chander, senior clinical researcher at King’s College London and lead author, said: “Our findings are remarkable and very surprising. We had a eureka moment when we discovered that our international colleagues had also found data that validated the discovery.”
Barbara Kasumu, chief executive of Guy’s Cancer Charity, which funded the study, said: “We are proud to be supporting Miguel and Anjali’s ground-breaking research, which aims to further our understanding of head and neck cancer and develop more compassionate and effective treatments.”