Cancer-Alcohol Link, 4

Especially as holidays seasons approach, make an informed choice based on the risks you are willing to take, as researchers have identified multiple ways that alcohol may increase the risk of cancer, including:

•  metabolizing (breaking down) ethanol in alcoholic drinks to acetaldehyde, a  toxic chemical that can damage DNA
•  generating chemically reactive molecules that contain oxygen, which can damage DNA, proteins, and lipids (fats) through a process called oxidation
• Impairing the body’s ability to break down and absorb a variety of micro nutrients
• Increasing blood levels of estrogen, a sex hormone linked to the risk of breast cancer
• Containing a variety of carcinogenic contaminants such as nitrosamines, asbestos fibers, phenols, and hydrocarbons 

http://www.cancer.gov/about-cancer/causes-prevention/risk/alcohol/alcohol-fact-sheet