Our DNA is a daily target for a barrage of damage caused by radiation or toxic substances such as alcohol. When alcohol is metabolized, acetaldehyde is formed. Acetaldehyde causes a dangerous kind of DNA damage — the interstrand crosslink (ICL) — that sticks together the two strands of the DNA. As a result, it obstructs cell division and protein production. Ultimately, an accumulation of ICL damage may lead to cell death and cancer. But there is repair system for this. The first line of defense against ICLs caused by acetaldehyde is the ALDH2 enzyme, that largely breaks down acetaldehyde before it causes any harm. However, not everyone profits from this enzyme — about half of the Asian population, more than 2 billion people worldwide, possess a mutation in the gene coding for this enzyme. Because they are not able to break down acetaldehyde, they are more prone to develop alcohol-related cancer.
— source Hubrecht Institute | Mar 4, 2020