Scientists have identified bacteria in the mouth that can speed up the growth of colorectal cancer.
Researchers at the Columbia University College of Dentistry recently determined how an oral bacteria called Fusobacterium nucleatum, often involved in tooth decay, accelerates the growth of colon cancer. The study was published online in the journal EMBO Reports.
Research shows that about a third of people who develop colorectal cancer are also carriers of the bacteria Fusobacterium nucleatum. These findings should help understand why some colorectal cancers grow much faster than others, say the scientists behind the study.
Discovery of a protein
Scientists have long known that this disease is caused by genetic mutations. “Mutations are only part of the story,” said Yiping W. Han, lead author of the study and professor of microbial science at Columbia University. “Other factors, including microbes, can also play a role,” he says. THEThe researchers noted the absence of a protein in healthy cells, but present in colon cancer cells. Called Annexin A1, said protein therefore stimulates cancer growth.
The scientists then carried out tests on laboratory mice, which consisted in canceling the action of Annexin A1. These tests showed that in the absence of this protein, the bacteria F. nucleatum finds it more difficult to attach to cancer cells, which would help stop the progression of the cancer.
More than 17,000 deaths from colorectal cancer in France
In an earlier study, Prof Han’s research team found that the bacteria make a molecule called adhesin FadA, triggering a signaling pathway in colon cells. They also found that FadA adhesin only stimulates the growth of cancer cells, not healthy cells. “We had to find out why F. nucleatum seemed to interact only with cancer cells,” said Professor Han.
Colon cancer is the second leading cause of cancer death in the United States. According to’American Cancer Society, the number of deaths linked to colorectal cancer for the year 2019 is estimated at more than 51,000. In 2015, 43,068 colon cancers were diagnosed in France (23,535 men and 19,533 women) and 17,833 deaths were identified (9,337 in men and 8,496 in women). The average age of the patients was 71 years for men and 75 years for women.
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