A new vaccine may soon protect women from developing breast cancer, say researchers.
The drug, which goes on trial within a year, can prevent tumour growth and also destroy tumours that are already present.
If the trials show positive results, researchers said doctors could offer it to women before they reach their mid-40s, when the risk of breast cancer starts to rise steeply.
Vincent Tuohy, the jab's creator, said it promised to offer "substantial protection" and raised the prospect of wiping out the disease permanently.
"We truly believe that a preventive breast cancer vaccine will do to breast cancer what the polio vaccine has done to polio," telegraph.co.uk quoted him as saying.
The vaccine is based on protein called alpha-lactalbumin that lurks in most breast cancer tumours.
In tests on mice bred to develop breast cancers by the age of 10 months, the drug was found to keep them free of tumours.
The jab stimulates the immune system, priming it to destroy alpha-lactalbumin as it appears, and so stopping tumours from forming.
The study appears in the journal Nature Medicine.