Research Findings Show Intestinal Escherichia coli Causes Colorectal Cancer

Probiotic Products May Cause Cancer

Dutch Utrecht University Researchers Publish Paper in 'Nature'

[Image source=AP Yonhap News]

[Asia Economy Reporter Kwon Jaehee] Research has found that Escherichia coli (E. coli) residing in the body can cause colorectal cancer.

Scientists at Utrecht University in the Netherlands published a paper on this topic in the scientific journal 'Nature' on the 27th (local time).

According to the paper summary, E. coli in the human body induces mutations with the same pattern as those found in colorectal cancer. It is known that 10-20% of the total population harbors this toxic E. coli species in their intestines.

Although the human body contains as many bacteria as cells, most are classified as beneficial bacteria that promote health. However, among some harmful bacteria that cause diseases, a representative is this genotoxin-producing E. coli species. This E. coli has been found to produce a chemical called colibactin, which damages human cell DNA.

In fact, E. coli strains widely used in health supplements have also been confirmed to potentially cause cancer after several years.

Hans Clevers, a professor of molecular genetics at Utrecht University, warned, "Probiotic products containing toxic E. coli are still being sold, and some are even used in clinical trials. While these probiotic products may relieve fatigue in the short term, they can cause cancer decades later."

Professor Clevers' research team exposed organoids cultured from healthy intestinal cells to E. coli for five months and then analyzed the DNA sequences to examine the types and amounts of mutations that occurred.

As a result, they successfully identified a unique genetic damage pattern, known as a 'signature,' left by the genotoxin-producing E. coli.

This E. coli species was found to create two simultaneous mutations.

Among the four bases that make up DNA code?adenine (A), guanine (G), cytosine (C), and thymine (T)?the pattern involved 'A' mutating into any other base, along with the deletion of one 'A' in a long sequence of repeated 'A's.

Colibactin produced by E. coli directly acts to bind or cross-link two 'A's simultaneously.

The research team then analyzed over 5,000 tumor mutations from dozens of cancer types and discovered that the E. coli signature was highly present in more than 5% of colorectal cancer tumors.

The E. coli signature was also found in some other cancers that can be exposed to E. coli, such as oral and bladder cancers, but the proportion was less than 0.1%.

Professor Clevers stated, "A critical laboratory re-evaluation of genotoxin-producing E. coli species is necessary," and personally recommended that individuals undergo carrier testing.