Scientists can now show how alcohol increases cancer risk by damaging DNA in stem cells. Previous research has looked at the precise ways alcohol causes cancer; however, it has only been done in cell cultures. In this new research, mice have been used to show how alcohol exposure leads to permanent genetic damage.
The study consisted of giving diluted alcohol, chemically known as ethanol, to mice. Then by using chromosome analysis and DNA sequencing, they were able to examine the genetic damage caused by acetaldehyde, the harmful chemical the body produces when processing alcohol.
What was discovered was the acetaldehyde can break and damage the DNA within blood stem cells. This led to the rearranging of chromosomes, which permanently altered the DNA sequences within these cells.
Understanding how the DNA blueprint within stem cells is damaged is important because when healthy stem cells become damaged, they can give rise to cancer. With the new findings, it has helped us to understand how alcohol increases the risk of developing seven different types of cancers, including common types like breast and bowel.
“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.”
How the body tries to protect itself against the damage was also studied. A family of enzymes called aldehyde dehydrogenases (ALDH) were seen to be the first line of defense. They broke down the harmful acetaldehyde into acetate, which our cells can then use as a source of energy.
Worldwide, millions of people either lack these enzymes or carry faulty versions of them. This causes the acetaldehyde to build up. It was found the mice that lacked the critical ALDH enzyme had as much as four times the DNA damage in their cells compared to mice with the enzyme.
During the second line of defense, the cells used a variety of DNA repair systems. In most cases, this allows them to fix and reverse different types of DNA damage. However, this does not always work. Some people carry mutations that may stop their cells from carrying out these repairs effectively.
Professor Patel added:
“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.
“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.”
Professor Linda Bauld, Cancer Research UK’s expert on cancer prevention, 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.”