Which statement is considered exception. (Text Comprehension)

LONDON (Reuters) - Drinking alcohol produces a harmful chemical in the body which can lead to permanent genetic damage in the DNA of stem cells, increasing the risk of cancer developing, according to research published on Wednesday.

Working with mice in a laboratory, British scientists used chromosome analysis and DNA sequencing to examine the genetic damage caused by acetaldehyde, a harmful chemical produced when the body processes alcohol.

Their findings offered more detail about how alcohol increases the risk of developing 7 types of cancer, including common forms such as breast and bowel cancer. It also showed how the body seeks to defend against the damage alcohol can do.“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,” said Ketan Patel, a professor at the Medical Research Council Laboratory of Molecular Biology, who co-led the study. The World Health Organization’s International Agency for Research on Cancer classifies alcohol as a Group 1 carcinogen, citing “convincing evidence” it causes cancer in humans.

In Wednesday’s study, published in the journal Nature, Patel’s team gave diluted alcohol to mice and then analyzed the effect on the animals’ DNA. They found that acetaldehyde can break and damage DNA within blood stem cells, permanently altering the DNA sequences within these cells.

This is important, Patel said, because when healthy stem cells become faulty, they can give rise to cancerous cells.

Source: www.reuters.com/article/us-health-cancer-alcohol/how alcohol-damages-stem-celldna-and-increases-cancer-risk-idUSKB1ES1N2