Gut bacteria linked to colon cancer risk

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A bacterium commonly found in the human gut may have a key role in the development of colon cancer, according to research due to be published in the Journal of Medical Microbiology.

US scientists discovered that Enterococcus faecalis – a normal gut bacterium – produces a molecule which activates signalling pathways that are associated with cancer cells.

Unlike most gut bacteria, E. faecalis is able to use fermentation to survive. It is a by-product of the process – an oxygen molecule called superoxide – which can damage DNA and may play a role in the formation of colon tumours.

The authors said: 'We found that superoxide from E. Faecilis 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 that are associated with cancer.'

Scientists have believed for several decades that some microbes living in the gut may contribute to the formation of sporadic colorectal cancer.