"Some cancers develop due to DNA damage in stem cells. While some damage occurs by chance, our findings suggest that drinking alcohol can increase the risk of this damage," Dr. Ketan Patel, who co-led the study, told Reuters.
The British scientists used DNA sequencing and chromosome analysis to study genetic damage caused by acetaldehyde. This harmful chemical is produced when the body processes alcohol. Studying mice, the researchers showed that acetaldehyde cuts through DNA, resulting in permanent damage.
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DNA has two layers of defense against acetaldehyde, one that clears it away and the other that repairs the damage. When these barriers were removed in the mice, the DNA damage accumulated until cells stopped working altogether.
The genomes of the their stem cells were sequenced by the researchers after they were exposed to acetaldehyde for a period of time. This showed that the cells' DNA was so mixed up that it no longer functioned.
Although the study focused specifically on stem cells in the blood, the scientists believe the effects could be similar in the body's other cells. Blood cells were chosen for the research as they multiply quickly, making DNA sequencing easier.
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While previous studies have examined the harmful effects of acetaldehyde, they relied on high concentrations of the chemical and never tested it on live subjects.
"Our study highlights that not being able to process alcohol effectively can lead to an even higher risk of alcohol-related DNA damage and therefore certain cancers," Patel told The Guardian. "But it's important to remember that alcohol clearance and DNA repair systems are not perfect and alcohol can still cause cancer in different ways, even in people whose defense mechanisms are intact."
Many previous studies linked alcohol consumption to cancer. According to the World Health Organization's International Agency for Research on Cancer, alcohol is classified as a Group 1 carcinogen, with the international body citing "convincing evidence" that it leads to cancer in humans.
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Commenting on the new study, leading scientific experts weighed in, praising the quality of the research.
"This is beautiful work which puts our finger on the molecular basis for the link between alcohol and increased cancer risk and stem cells," Dr. Magdalena Zernicka-Goetz, Professor of Mammalian Development and Stem Cell Biology at Cambridge, said, according to The Telegraph.
Dr. Malcolm Alison, Professor of Stem Cell Biology at the Barts Cancer Institute, Queen Mary University of London, warned drinkers to "beware," referencing the findings.
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"Most of our organs and tissues have stem cells, immortal cells that replenish cells lost through the likes of old age throughout our lives, and the haematopoietic (blood stem cell) system is no exception," he said.
As Dr. Linda Bauld, an expert on cancer prevention at Cancer Research UK, which partly funded the research, pointed out, the research demonstrates that alcohol consumption may be "costing some people more than just a hangover."