Trial raises hopes for anti-breast cancer jab

US researchers said the vaccine showed "overwhelmingly favourable results" in mice – preventing cancers from forming and also stopping existing tumours from growing.

"If it works in humans the way it works in mice, this will be monumental," said lead researcher, immunologist Dr Vincent Tuohy.

Human tests could begin as early as next year.

Dr Tuohy, of Cleveland Clinic in the US, said: "We believe that this vaccine will some day be used to prevent breast cancer in adult women in the same way that vaccines have prevented many childhood diseases.

"If it works in humans the way it works in mice, this will be monumental. We could eliminate breast cancer."

The drug makes the immune system attack a particular protein found in most breast cancer cells and the mammary tissues of breastfeeding women.

If tests prove successful, the strategy would be to vaccinate women over 40 when breast cancer risks increase and pregnancy becomes less likely.

Caitlin Palframan, of charity Breakthrough Breast Cancer, warned the research was at a very early stage and large-scale clinical trials were needed to find out if the vaccine was safe, which could take many years. She urged women to cut their cancer risk by reducing alcohol consumption, and through a healthy diet and exercise.