http://www.digitaljournal.com/article/362224

Studying gut bacteria to determine tumor risk

Posted Nov 16, 2013 by Tim Sandle
Inflammation appears to play a role in the development of colorectal cancer, and this inflammation is triggered by certain gut bacteria, which some people possess and others do not.
A stain of the bacterium Bacteroides biacutis
A stain of the bacterium Bacteroides biacutis
US CDC
The new research findings suggest that changes in the gut microbiota create the conditions that result in colon tumors triggering colorectal cancer. Colorectal cancer, also known as colon cancer, rectal cancer, or bowel cancer, is a cancer from uncontrolled cell growth in the colon or rectum.
To show this, researchers identified suspect microbial communities and transferred these into mice. The suspect bacteria were of the Bacteroides, Odoribacter, and Akkermansia genera. These bacteria are not uncommon, but the numbers present in the body are normally low.
Next, the researchers studied whether tumors occurred or not. What they found was that the development of tumors was twice as likely in mice has had received the probable cancerous community of microbes.
One of the risk factors in patients, in addition to diet and lifestyle, is considered to be a shift in the microbial population of the gut (a condition known as dysbiosis).
The study has implications for human health because it indicates the risk of colorectal cancer may well have a microbial component. What is unknown is whether environmental factors trigger a shift in the bacterial population of the gut (and thus increasing the cancer risk) or whether a change to the bacteria in the gut makes people more vulnerable to different environmental factors. For this conundrum, more research is needed.
The research was undertaken at the University of Michigan and the findings have been published in mBio®, the online open-access journal of the American Society for Microbiology. The paper is titled “The Gut Microbiome Modulates Colon Tumorigenesis.”