Species of bacteria in the mouth can "melt away" cancer
Bacteria usually associated with the spread of colon cancer, a British research team has now found the opposite in the most common type of head and neck cancer: the bacteria destroy the tumor cells.
Bacteria against cancer? British scientists have discovered that a common type of oral bacteria can cause certain types of cancer to "melt away." Patients with head and neck cancer who have fusobacteria in their tumors have significantly better chances of recovery, according to a study published in the journal "Cancer Communications."
In a laboratory test, the research team led by Miguel Reis Ferreira, a specialist in head and neck cancer at Guy's and St Thomas' NHS Foundation Trust, placed a certain amount of the bacteria in petri dishes with cancer cells. The result surprised the researchers: after just a few days, the cancer was almost completely gone. The number of viable cancer cells in head and neck cancer cells decreased by 70 to 99 percent after infection with fusobacteria, the team writes.
A subsequent analysis of 155 patient data showed that those who had fusobacterium in their cancer had better survival chances than those who did not. The presence of fusobacteria in head and neck tumors was associated with a 65 percent lower risk of death than in patients whose tumors did not contain the bacteria.
Surprising result
The research team had originally expected a different result, as previous studies have linked fusobacteria to the progression of colon cancer. "We assumed that the fusobacterium would also promote the growth of head and neck cancer or make them more resistant to radiation therapy," Reis Ferreira told the PA news agency. "Instead, we observed that it completely destroyed the cancer after a few days." Even very small amounts of the bacterium were sufficient for this.
The results show that these bacteria play a more complex role in cancer than previously known, the study author said. He hopes that the new findings could be helpful in the treatment of patients with head and neck cancer, which includes cancer of the mouth, throat, larynx, nose, and nasal sinuses. In addition, fusobacteria could serve as a biomarker for how patients will respond to treatment.
However, how the bacteria destroy the tumor is not entirely clear. The researchers suspect that they directly kill the cancer cells and also trigger an immune response against the tumor. This will have to be investigated in more detail in further studies.
First attempts over 100 years ago
There have been attempts to combat cancer with bacteria for over 100 years. A doctor had observed in the 1890s that some of his cancer patients recovered or even became completely healthy if they caught an infection after a cancer operation. His subsequent attempts to develop a treatment based on these observations were not very successful, so the method has not been further researched until now. This could change with the new findings about fusobacteria.
Despite previous studies linking fusobacteria to the progression of colon cancer, this British research team found an unexpected outcome in head and neck cancer, the most common type in their study. Contrary to expectations, fusobacteria were found to destroy tumor cells, leading to significantly better recovery chances for patients with head and neck cancer who had this bacterium in their tumors.
