In the last ten years there has been an increasing amount of evidence to suggest that alcohol can increase the risk of some cancers. A new study into the link between alcohol and cancer has shown that in some cases it can cause irreversible genetic damage to stem cell reserves. During the study, genetically modified mice were used to prove that alcohol can cause DNA damage that could cause cancer causing mutations.

“How exactly alcohol causes damage to us is controversial,” said Prof Ketan Patel, who led the work at the MRC Laboratory of Molecular Biology in Cambridge. “This paper provides very strong evidence that an alcohol metabolite causes DNA damage [including] to the all-important stem cells that go on to make tissues.”

“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,” he added. “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 defence mechanisms are intact.”

The study has shown that acetaldehyde can slice through DNA, which can cause permanent damage if the effects are not neurtalised by the body’s natural defences. After scientists had removed both these defences, they were able to see how the DNA damage accumulated, to the point where the cells stopped working altogether.

There was also evidence that the level of DNA damage was significantly higher when aldehyde dehydrogenase 2 (ALDH2), the protective enzyme that helps to prevent a build-up of acetaldehyde in the body, was lacking in the mice. An estimated 8% of the global population are deficient in ALDH2, and those of Eastern Asian decent are much more likely to be affected, which could provide an explanation as to the increased rates of oesophageal cancers in those countries.  

Researchers plan to investigate why alcohol increases the risk of throat, oesophageal, breast and bowel cancers, yet doesn’t seem to cause any increase in the risk of blood cancer when the study shows that it can affect the DNA in blood stem cells.  “Actually the blood system has a very stringent quality control mechanism to get rid of anything that is damaged,” said Patel.

Prof Magdalena Zernicka-Goetz, a stem cell biologist at the University of Cambridge, said “This is beautiful work which puts our finger on the molecular basis for the link between alcohol and increased cancer risk and stem cells.”

Prof Linda Bauld, an expert on cancer prevention at Cancer Research UK, which partly funded the research, said: “This thought-provoking research highlights the damage alcohol can do to our cells, costing some people more than just a hangover. We know that alcohol contributes to over 12,000 cancer cases in the UK each year, so it’s a good idea to think about cutting down on the amount you drink.”

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