Bovine Meat and Milk Factors (BMMFs) are novel infectious agents generally found in dairy products and bovine sera. Do they play a role in the development of colorectal cancer?
In a significant development, scientists led by Harald zur Hausen detected the pathogens in colorectal cancer patients in close proximity to tumors.
They have found evidence of BMMFs triggering local chronic inflammation.
This inflammation can cause mutations via activated oxygen molecules and thus promote cancer development in the long term.
BMMFs and inflammatory markers were significantly more frequently detectable in the vicinity of malignant intestinal tumors than in the intestinal tissue of tumor-free individuals.
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What Are Bovine Meat and Milk Factors (BMMFs)?
They are infectious agents generally found in dairy products and bovine sera. The ring-shaped DNA elements were first discovered by scientists at the German Cancer Research Center (DKFZ). Scientists led by Ethel-Michele de Villiers found these elements similar to sequences of certain bacterial plasmids. Since they were found in bovine products, the scientists decided to name them Bovine Meat and Milk Factors (BMMFs).
De Villiers, together with Harald zur Hausen, had tracked down the infectious agents while testing a hypothesis: Based on epidemiological observations, the Nobel Prize winner zur Hausen had postulated a possible link between the consumption of beef or dairy products and the incidence of colorectal cancer. “It seemed likely to us that an infectious agent transmitted from European domestic cattle to humans was associated with the development of colorectal cancer,” zur Hausen said.
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Meanwhile, de Villiers was able to isolate more than a hundred different agents from dairy products. The BMMFs can multiply in human cells, where they produce a protein product, Rep, which they need to multiply. But how might they contribute to the development of colorectal cancer?
Scientists from Timo Bund’s team at the DKFZ have now carefully investigated this question using tissue samples from colorectal cancer and from healthy intestine. To detect the pathogens, the researchers used antibodies generated against the Rep protein. This enabled them to detect BMMFs in 15 of 16 colorectal cancer tissue samples.
Another indication of inflammatory processes were the elevated levels of reactive oxygen species that Ethel-Michele de Villiers, Timo Bund and colleagues detected in the environment of Rep-positive cells. ”
“We regard BMMFs as indirect carcinogens, which probably act on the dividing cells of the intestinal mucosa for decades,” zur Hausen said. He hypothesizes that infection with BMMFs usually occurs early in life, around the time of weaning.
“The results support our hypothesis that the consumption of milk and beef are causally linked to the development of colorectal cancer, and at the same time open up possibilities for preventive intervention,” explains zur Hausen. For example, early detection of BMMFs could identify individuals who are particularly at risk, who should then seek timely colorectal cancer screening.