London, Jan 4 (PTI) Alcohol consumption permanentlydamages the DNA in stem cells, which in turn increases therisk of developing cancer, a study led by an Indian-originscientist warns.
Much previous research looking at the precise ways inwhich alcohol causes cancer has been done in cell cultures.
However, in the new study, researchers used mice to showhow alcohol exposure leads to permanent genetic damage.
Scientists at the MRC Laboratory of Molecular Biology atthe University of Cambridge in the UK gave diluted alcohol,chemically known as ethanol, to mice.
They then used chromosome analysis and DNA sequencing toexamine the genetic damage caused by acetaldehyde, a harmfulchemical produced when the body processes alcohol.
The researchers found that acetaldehyde can break anddamage DNA within blood stem cells leading to rearrangedchromosomes and permanently altering the DNA sequences withinthese cells.
"Some cancers develop due to DNA damage in stem cells,"said Professor Ketan Patel from the MRC Laboratory ofMolecular Biology.
"While some damage occurs by chance, our findings suggestthat drinking alcohol can increase the risk of this damage,"said Patel, lead author of the study published in the journalNature.
It is important to understand how the DNA blueprintwithin stem cells is damaged because when healthy stem cellsbecome faulty, they can give rise to cancer, researchers said.
The new findings help us to understand how drinkingalcohol increases the risk of developing seven types of cancerincluding common types like breast and bowel, they said.
The study also examined how the body tries to protectitself against damage caused by alcohol. The first line ofdefence is a family of enzymes called aldehyde dehydrogenases(ALDH).
These enzymes break down harmful acetaldehyde intoacetate, which our cells can use as a source of energy.
Worldwide, millions of people, particularly those fromSouth East Asia, either lack these enzymes or carry faultyversions of them, researchers said.
When they drink, acetaldehyde builds up which causes aflushed complexion, and also leads to them feeling unwell,they said.
In the study, when mice lacking the critical ALDH enzyme- ALDH2 - were given alcohol, it resulted in four times asmuch DNA damage in their cells compared to mice with the fullyfunctioning ALDH2 enzyme.
The second line of defence used by cells is a variety ofDNA repair systems which, most of the time, allow them to fixand reverse different types of DNA damage.
However, they do not always work and some people carrymutations which mean their cells are not able to carry outthese repairs effectively.
"Our study highlights that not being able to processalcohol effectively can lead to an even higher risk ofalcohol-related DNA damage and therefore certain cancers,"Patel said.
"But it is important to remember that alcohol clearanceand DNA repair systems are not perfect and alcohol can stillcause cancer in different ways, even in people whose defencemechanisms are intact," he added. PTI SARSAR.
This is unedited, unformatted feed from the Press Trust of India wire.