Studies using transgenic mice have provided the most convincing evidence to date that alcohol causes cancer by disrupting DNA in cells and eventually leads to deadly mutations.
In the past decade, more and more evidence shows that there is a link between drinking alcohol and the risk of certain cancers.
Professor Ketan Patel, director of the MRC Laboratory for Molecular Biology at the University of Cambridge, said: “How alcohol can cause harm to us is controversial.” This paper provides compelling evidence that alcohol metabolites cause DNA damage [including] causing tissue The important stem cells. ”
This study, based on previous studies, identified the breakdown product of ethanol, called acetaldehyde, that can destroy intracellular DNA. However, these earlier studies relied on very high concentrations of acetaldehyde and used cells rather than on their role in the body.
Recent research shows that if the toxin is not neutralized by two natural defense mechanisms, acetaldehyde cuts through the DNA, causing permanent damage. The first line of defense removes acetaldehyde and the second repairs DNA damage.
By gene-knocking off these two defenses, scientists can show the accumulation of DNA damage until the cells eventually stop working altogether.
Studies show that when mice lack the first line of defense, a protective enzyme called aldehyde dehydrogenase 2 (ALDH2), DNA damage is aggravated, preventing the potential accumulation of acetaldehyde toxicity. About 8% of the world’s population, mainly East Asian descent, has a genetic defect in ALDH2 (sometimes referred to as a flushing mutation), which can explain the high incidence of esophageal cancer in countries like China.
The study, published in Nature, focuses on stem cells in the blood, and stem cells in the blood rely on the stem cells to provide fresh blood throughout their lives. Blood cells are singled out because they can be easily multiplied to make DNA easier to sequence, but scientists believe the alcohol effects of other cell types may be similar.
The study found that in mice lacking natural defensive alcohol, the ability to produce fresh blood was completely destroyed after 10 days of diluting the alcohol. Sequencing stem cell genomes shows that their DNA has been mixed up to the point where the cell is no longer functional.
Patel said: “Our research emphasizes that failure to treat alcohol effectively results in a higher risk of alcohol-related DNA damage and as a result, it causes some cancers.” But it’s important to remember that alcohol clearance and DNA repair systems are not perfect , Alcohol can still cause cancer in different ways, even in people with intact defense mechanisms.
The team now plans to investigate why alcohol consumption is associated with certain cancers rather than with other cancers.
Alcohol consumption in the UK accounts for about 4% of cancer, about 12,800 cases a year. Drinking only a serving of beer or a glass of wine per day greatly increases the risk of mouth, throat, esophagus, breast and bowel cancer. But experts say there is no evidence of a significant increase in the risk of cancer among drinkers, although new findings show that drinking water can alter DNA in blood stem cells.
“In fact, the blood system has a very strict quality control mechanism to get rid of any damage,” Patel said, adding that this may explain why alcohol abuse tends to be severe anemia. Defense mechanisms for acetaldehyde in other tissues may be weak.
Professor Magdalena Zernicka-Goetz, a stem cell biologist at the University of Cambridge, said the finding is important: “It’s a wonderful job to put our fingers on the basis of the link between alcohol and increasing the risk of cancer and stem cells ,”she says.
Professor Linda Bauld, cancer prevention expert at Cancer Research UK, said: “This thought-provoking study highlights the damage alcohol can cause to our cells, making some people more than just hangovers.
“We know there are over 12,000 cancer cases in the UK each year, so reducing alcohol consumption is a good idea.”