How diarrheal bacteria cause some colon cancers revealed in mou...(In ETBF-infected mice they found high le...),Health

Th17 activity in the gut of germ-bearing mice was 100 times greater than normal, according to the investigators, and when they blocked the effects of Th17, they were able to reverse inflammation and tumor growth.

Drew Pardoll, M.D., Ph.D., an immunologist and cancer researcher at Johns Hopkins, speculates that in humans, infection with ETBF "produces a low-level inflammation that persists for a long time."

"If what we are seeing in mice holds true in humans, the chronic inflammation damages genetic material in the colon cells, allowing them to grow uncontrollably and develop into tumors earlier and more progressively than if they were not infected with ETBF," Pardoll says.

Sears first witnessed the impact of diarrheal pathogens two decades ago in a refugee camp in Thailand where children, especially, were vulnerable to infection where water sanitation is poor. Most diarrheal disease is short-lived but can be very severe, Sears says, and it is common worldwide. The ETBF microbe is found in the gut of up to 20 to 35 percent of children and adults and, according to the Turkish study, in as many as 40 percent of colon cancer patients.

Sears and Pardoll believe that ETBF may collude with other types of normal bacteria in the gut to promote cancer. The microbe itself is difficult to culture from stool specimens, according to the investigators, so they are working on blood tests to detect antibodies to the pathogen's toxin, which may show whether an individual has been exposed to it and perhaps determine who may be at risk for colon cancer.

The investigators also envision vaccines and drug therapies that neutral
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