Scientists have brought cancer cells back under normal control by reactivating their cancer suppressor genes.
The discovery by University of Nottingham researchers could form a powerful new technology platform for the treatment of cancer of the breast and other cancers.
A common cause of cancer is when cells are altered or mutated and the body's tumour suppressor genes are switched off.
After 60 days there was still no evidence of cancerous growth.
The finding was published today in the Journal Molecular Cancer.