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How gut bugs could trigger cancer | How gut bugs could trigger cancer |
(about 8 hours later) | |
Scientists have uncovered a chain reaction which could link a type of bacterium living in our intestines to the development of colon cancer. | Scientists have uncovered a chain reaction which could link a type of bacterium living in our intestines to the development of colon cancer. |
Enterococcus faecalis is harmless in the vast majority of people, but US scientists have found that it can produce harmful chemicals. | Enterococcus faecalis is harmless in the vast majority of people, but US scientists have found that it can produce harmful chemicals. |
The Journal of Medical Microbiology study found these can damage DNA, and prompt gene activity linked to cancer. | The Journal of Medical Microbiology study found these can damage DNA, and prompt gene activity linked to cancer. |
A UK expert said it was plausible that bacteria could cause colon cancer. | A UK expert said it was plausible that bacteria could cause colon cancer. |
However, he stressed that E.faecalis was very unlikely to be the only bacterium which had such an effect. | However, he stressed that E.faecalis was very unlikely to be the only bacterium which had such an effect. |
This research puts into perspective the complexity of the effects normal gut bacteria can have on the health of the individual Professor Mark HuyckeResearcher | This research puts into perspective the complexity of the effects normal gut bacteria can have on the health of the individual Professor Mark HuyckeResearcher |
Our guts provide a home to dozens of different types of bacteria, many of which actually provide a useful service, helping break down indigestible sugars in food by fermentation, or even "training" the body's immune system. | Our guts provide a home to dozens of different types of bacteria, many of which actually provide a useful service, helping break down indigestible sugars in food by fermentation, or even "training" the body's immune system. |
However, in recent years, scientists have suggested that in certain, susceptible individuals, these bacteria can actually do harm. | However, in recent years, scientists have suggested that in certain, susceptible individuals, these bacteria can actually do harm. |
E.faecalis, sometimes also known as Group D Streptococcus, is one of those under suspicion, and the research by the Department of Veterans Affairs Medical Center in Oklahoma City strengthens the link. | E.faecalis, sometimes also known as Group D Streptococcus, is one of those under suspicion, and the research by the Department of Veterans Affairs Medical Center in Oklahoma City strengthens the link. |
The researchers investigated how colon cells in the laboratory reacted to the presence of the bacterium, when it is in a "fermentation" state. | The researchers investigated how colon cells in the laboratory reacted to the presence of the bacterium, when it is in a "fermentation" state. |
In this state, it produces a kind of oxygen molecule called "superoxide", and it is this which can damage DNA in surrounding cells. | In this state, it produces a kind of oxygen molecule called "superoxide", and it is this which can damage DNA in surrounding cells. |
Gene activity | Gene activity |
Professor Mark Huycke, who led the research, found that the apparent effects were not limited to this. | Professor Mark Huycke, who led the research, found that the apparent effects were not limited to this. |
"We found that superoxide led to strong signalling in immune cells called macrophages - it also altered the way some cells in the gut grew and divided and even increased the productivity of genes which are associated with cancer." | "We found that superoxide led to strong signalling in immune cells called macrophages - it also altered the way some cells in the gut grew and divided and even increased the productivity of genes which are associated with cancer." |
In total, the expression of 42 genes linked to vital processes in human cells was altered by the presence of E. faecalis in this state. | In total, the expression of 42 genes linked to vital processes in human cells was altered by the presence of E. faecalis in this state. |
"This research puts into perspective the complexity of the effects normal gut bacteria can have on the health of the individual." | "This research puts into perspective the complexity of the effects normal gut bacteria can have on the health of the individual." |
Dr Barry Campbell, a gut microbiology researcher from the University of Liverpool, agreed that E.faecalis was a candidate for cancerous changes. | Dr Barry Campbell, a gut microbiology researcher from the University of Liverpool, agreed that E.faecalis was a candidate for cancerous changes. |
However, he said that other bowel bacteria could also be behind the cell changes which eventually lead to tumours. | However, he said that other bowel bacteria could also be behind the cell changes which eventually lead to tumours. |
He said: "There is not going to be only one culprit. Our own team is interested in a particular type of E.coli with this in mind. | He said: "There is not going to be only one culprit. Our own team is interested in a particular type of E.coli with this in mind. |
"There are also many other factors which are involved, such as genetics and environment." | "There are also many other factors which are involved, such as genetics and environment." |
Professor Ian Rowland, a specialist in gut bacteria from Reading University, said: "This shows how it could happen, although whether this actually does happen in a human is another matter. | |
"There is a lot of circumstantial evidence that gut bacteria are important in colorectal cancer, although we don't fully understand why. | |
"In the case of Enterococcus faecalis, we know that most people have this in their gut, but most people don't get colon cancer, so there must be other factors involved." |
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