New York: Drinking just two glasses of wine a day raises a woman’s risk of breast cancer, say researchers at the University of Mississippi Medical Centre.

In an animal experiment, female mice given the human equivalent of two alcoholic drinks a day, developed breast tumours twice the size of those given none.

The six-week old mice were fed moderate amounts of alcohol over a four week period.

Lead researcher Jian-Wei Gu said alcohol consumption is the most important avoidable risk factor for women in contracting breast cancer.

The conclusion is based on the fact that studies in mice mimic the results in humans. It is thought that the increase in tumour size is a result of an increase in blood flow through vessels caused by the alcohol.