Cancer-Fighting Microbes

Scientists have turned a common disease-causing microbe into a potential lifesaver. Salmonella bacteria are best known for causing severe food poisoning, resulting in nausea, fever, and diarrhea. But scientists in South Korea recently modified a harmless version of the microbe to destroy cancerous tumors—masses of abnormal cells—in mice.

A tumor forms when DNA inside a cell develops certain mutations. These changes cause the cell to divide uncontrollably. The body’s immune system, which normally defends against diseases, doesn’t recognize the tumor as a threat because it’s made of the body’s own cells.

Salmonella bacteria multiply rapidly in cancerous tumors. In the study, scientists injected the engineered Salmonella into mice with tumors. The bacteria activated immune cells in the tumors. When the immune system attacked the germs, it often destroyed the tumor in the process: 60 percent of tumors in the mice disappeared in just a few weeks.

“Combining bacterial therapy with current cancer treatments could have promising results for humans in the future,” says Vu Nguyen, a biologist who took part in the study.