Strikingly high levels of a bacterium have been found identified in samples taken from colorectal cancer patients, suggesting the bacterium may contribute to the disease, a study published online in Genome Research reports.
Researchers from Boston in the US found abnormally large number of Fusobacterium cells in nine colorectal tumour samples which underwent DNA sequencing. A confirmed connection between Fusobacterium and the onset of colorectal cancer would mark the first time any microorganism has been found to play a role in this type of cancer.
The researchers hope that the bacterium could act as a key to diagnosing, preventing, and treating the disease. Matthew Meyerson, co-director of the Center for Cancer Genome Discovery at Dana-Farber and professor of pathology at Harvard Medical School, said: "Tumours and their surroundings contain complex mixtures of cancer cells, normal cells, and a variety of microorganisms such as bacteria and viruses. Over the past decade, there has been an increasing focus on the relationship between cancer cells and their 'microenvironment,' specifically on the cell-to-cell interactions that may promote cancer formation and growth."
While the relationship – if any – between colorectal cancer and Fusobacterium is unclear, there are intriguing hints that the bacterium may play a role in the cancer, he added. Previous studies have suggested that Fusobacterium is associated with inflammatory bowel diseases such as ulcerative colitis, which can raise people's risk of developing colon cancer.
"At this point, we don't know what the connection between Fusobacterium and colon cancer might be," Professor Meyerson said. "It may be that the bacterium is essential for cancer growth, or that cancer simply provides a hospitable environment for the bacterium. Further research is needed to see what the link is."