Researchers at the University of Liverpool have isolated a variety of E. coli that can promote colon cancer.
The same team had previously shown that people with colon cancer and other diseases such as inflammatory bowel diseases, Crohn's disease and ulcerative colitis have increased numbers of a sticky type of E. coli in their colons.
AdvertisementThey discovered that the pks genes found in these E.coli is capable of damaging the DNA of cells lining the gut. These damaging bacteria are more commonly found in the colons of patients with inflammatory bowel disease and colon cancer than in those who are healthy. On an average it was found that two thirds of patients with colon cancer carry these E. coli, compared to its presence in one in five people whose colons were healthy.
Other studies have shown that mice that suffered from colitis were more likely to develop colon cancer if they harbored E. coli containing pks genes but were observed not to develop cancer if it carried another strain of identical E.coli that did not harbor pks genes. The presence of these genes, however, did not cause increased inflammation of the gut. It was the ability of pks genes to cause cancer without causing inflammation that prompted studies on its role in colon cancer.
The increased presence of the E.coli in the colon of patients with inflammatory bowel disease, and also in those with colon cancer who do not suffer from inflammatory bowel disease, suggests that toxins generated by the pks genes have a deleterious effect on the DNA and can promote colon cancer.
The research has implicated that E. Coli has a much deeper involvement in the development of colon cancer than previously thought and it is important to understand why these bacteria are present in some types of people and not in others.
Earlier research by the Liverpool team also discovered that dietary agents, particularly plantain and broccoli, could prevent the promotion and transport of E. coli through the gut cells, while fat emulsifiers found in processed foods encouraged the transport of bacteria through gut cells.