According to two new investigations published online in Genome Research , independent investigation teams have for the first time discovered a specific microorganism called Fusobacterium to be linked with human colorectal cancer. The discovery of the bacterium in colon cancer tissue could help to pave the way for new diagnosis and treatment strategies of the cancer.

Colon cancer is the second leading cause of cancer deaths, and even though inflammation is known to be a risk factor, the fundamental cause is still not clear. In the past gastric cancers have been associated to inflammation mediated by the microorganism H. pylori, which makes it possible that a few of the several microbes species found in the gut could be linked with colorectal cancers.

The two independent teams found a potential association between colon cancer and a microorganism after they identified that Fusobacterium, a single genus of bacteria, was found more often in colon cancer tissue compared to normal tissue.

Dr. Robert Holt of the BC Cancer Agency and Simon Fraser University, and senior author of one of the reports explains:

“This was especially surprising because although Fusobacterium, the bacterium we found in colon tumors, is a known pathogen, it is a very rare constituent of the normal gut microbiome and has not been associated previously with cancer.”

Dr. Matthew Meyerson of the Dana-Farber Cancer Institute and senior author of the other study said:

“It was also surprising that … Fusobacterium has also previously been reported to be associated to be with ulcerative colitis, which is itself a risk factor for colon cancer.”

Holt’s team found Fusobacterium by sequencing RNA from normal colon tissue and comparing it with the RNA present in colon cancer tissue. They looked for sequences that stemmed from microorganisms. Meanwhile, in order to find microbial sequences, Meyerson’s group sequenced the DNA present in normal tissues and cancer tissues.

Both Holt and Meyerson stated that even though it is currently unclear if Fusobacterium infection is a cause or consequence of colorectal tumors, it could be extremely helpful in the clinic as a indicator for cancer. If the bacteria is discovered to be causative for disease, clinical trials could assess how effective vaccines or antibiotics prevent or treat cancer.

Written by Grace Rattue