Alcohol Consumption Increases the Risk of Cancer

While alcohol consumption in general is associated with several health risks including cancer, new study shows how drinking alcohol can increase the risk for developing cancer by causing changes to our genome. The study was partly funded by the Cancer Research UK and published in Nature. While most previous studies on the issue were alcohol leads to cancer were done in lab cell cultures, this study shows the same in a live animal model.

Study Overview

The research team from the MRC Laboratory of Molecular Biology, Cambridge has used mice to show how alcohol exposure can lead to permanent genetic damage in stem cells thereby increasing the chances of cancer development. The mice were given diluted alcohol, known as ethanol. Following this a chromosomal analysis and DNA sequencing were performed to analyze the changes in the mice DNA.

When alcohol is consumed and processed by the body, acetaldehyde, a harmful chemical is produced as a result. This, the study has found can break DNA bonds within blood stem cells. Breaking of bonds can result in rearrangement of chromosomes and alteration of the genetic material, causing permanent damage to cells. These altered stem cells can lead to cancer if the basic properties are altered.

The study shows how alcohol based DNA changes can increase the risk for 7 different types of cancer including breast and bowel cancer which are very common.

The role of aldehyde dehydrogenases

Professor Ketan Patel, lead author of the study said: "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."

A class of enzymes called aldehyde dehydrogenases (ALDH) is the first line of defence to protect the body from the negative effects of alcohol. They break down acetaldehyde into acetates which can be used up by cells as a source of energy.

However millions of people, especially those in South East Asia lack this class of enzymes or have non-functional copies as a result of mutation. In these individuals, regular consumption of alcohol causes problems as the harmful by-product cannot be broken down due to lack of enzymes.

In the study, when mice that had mutated ALDH enzyme were given alcohol, there were four times as much DNA damage in their cells compared to mice with functioning enzyme.

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Professor Patel concludes, "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 defence mechanisms are intact."

Reference:

1. Juan I. Garaycoechea, Gerry P. Crossan, Frédéric Langevin, Lee Mulderrig, Sandra Louzada, Fentang Yang, Guillaume Guilbaud, Naomi Park, Sophie Roerink, Serena Nik-Zainal, Michael R. Stratton, Ketan J. Patel. Alcohol and endogenous aldehydes damage chromosomes and mutate stem cells. Nature, 2018; DOI: 10.1038/nature25154

Source-Medindia