Breast cancer treatment could soon include a drug which is normally part of diabetic medication.
Researchers at Seoul National University have found that metformin can help reduce the risk of breast cancer by preventing some carcinogens from initiating the growth of tumour cells.
The doctors believe this finding is especially relevant as sufferers of type 2 diabetes often have a higher chance of developing several forms of the disease, such as breast, liver and pancreatic cancer.
Professor James Trosko said that although more work needed to be done, metformin appears to prevent oestrogen and man-made chemicals from turning stem cells cancerous.
"This study reveals the need to determine if the drug might be used as a preventive drug and for individuals who have no indication of any existing cancers," he added.
According to Cancer Research UK, breast cancer is the most common form of the disease in the UK and 12,116 deaths were attributed to the illness in 2008.