People who drink and carry two hereditary cancer genes are at an increased risk of cancer owing to an alcohol by-product, says a study.

Scientists have shown that people carrying certain mutations in two hereditary cancer genes – BRCA2 and PALB2 – may have a higher than usual susceptibility to DNA damage caused by a by-product of alcohol – called acetaldehyde.

Acetaldehyde is produced during the metabolism of alcohol and is known to cause DNA damage. The research suspects that the two genes in their normal forms evolved to protect cells against the damaging effects of acetaldehyde, which can lead to cancer.

“Though the research is preliminary, the findings suggest that studies on disease risk factors should take into account these particular genetic variations and the use of alcohol,” said Scott Kern, the Everett and Marjorie Kovler professor in pancreas cancer research at Johns Hopkins University in the US.

“We need to identify which behaviours in certain populations increase disease risk, and keep in mind that our genetic susceptibility plays a large role in cancer risk,” Kern added.

Found in many sources including apples and gut bacteria, acetaldehyde is ubiquitous in nature and is responsible for the hangovers people experience after heavy alcohol use.

The scientists found that BRCA2 and PALB2-mutant cell lines exposed to acetaldehyde had up to 25 times more growth reduction when compared with related cells lacking these mutations.

The significant reduction in cell growth indicates that these cell lines, which lack the two genes, are more susceptible to the DNA damage caused by acetaldehyde, added the scientists.