(CBS) Do germs cause colorectal cancer? Two provocative new studies suggest they might after scientists found the presence of a well-known bacterial pathogen in colon cancer tissue samples.
For the studies - both published in the Oct. 17 issue of the journal Genome Research - scientists sequenced both the DNA and RNA of colon cancer and normal tissue samples. Both teams of scientists discovered that the so-called Fusobacterium microorganism is found significantly more often in cancerous tissue.
"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...and has not been associated previously with cancer, " one of the study's authors Dr. Robert Holt, an immunogenetics researcher at the BC Cancer Agency in Vancouver, said in a written statement.
In some samples, the scientists found hundreds of times more of the bacteria in cancerous tissues than in healthy ones.
Previous research has linked Fusobacterium to ulcerative colitis, a risk factor for colon cancer, according to Dr. Matthew Meyerson, a genetic researcher at Harvard's Dana-Farber Cancer, and author of the second study. His team also saw the bacteria was present in colon cancer tissue samples.
"I don't know what to make of it," Dr. Meyerson told the New York Times. "The bacteria are hanging around the tumors, but I have no idea if they spur or cause cancer."
While both teams of scientists wrestle to confirm whether Fusobacterium is a cause or effect of colorectal cancer, they're hopeful the bacterial discovery could lead to antibiotics and vaccines that fight the second deadliest cancer.
More than 101,000 new cases of colon cancer are diagnosed each year, along with nearly 40,000 cases of rectal cancer. Combined, colorectal cancer kills more than 49,000 people each year.
The American Cancer Society has more on colorectal cancer.