Diabetes drug metformin could help lower breast cancer risk

A new study from South Korea has found that the diabetes drug metformin could help to reduce the risk of diabetes-associated cancers, such as breast cancer. The research offers further evidence supporting such benefits of long-term treatment by metformin, which is taken by patients with type 2 diabetes and helps to prevent cardiovascular complications.
The team examined if cancers originate from adult stem cells and how many types of chemicals can enhance the growth of breast cancer cells, by growing miniature human breast tumours, called mammospheres, in culture dishes. This activated a stem cell gene, before the mammospheres were exposed to both natural oestrogen and man-made chemicals that can promote tumours or cause problems for the endocrine system.
The oestrogen and chemicals resulted in the mammospheres increasing until the introduction of metformin, which radically lowered the amount and size of the mammospheres.
Study leader James Trosko, from Seoul National University, commented “People with Type-2 diabetes are known to be at high risk for several diabetes-associated cancers, such as breast, liver and pancreatic cancers.”
He added “Though we still do not know the exact molecular mechanism by which it works, metformin seems to dramatically affect how oestrogen and endocrine-disrupting chemicals cause the pre-existing breast cancers to grow.”