CHICAGO (Reuters) – The common diabetes drug metformin may hold promise as a way to keep smokers from developing lung cancer, US researchers said this week. They said metformin prevented lung tumour growth in mice exposed to a cancer-causing agent found in tobacco smoke, and because it is already widely used in people, it may be worth further study.

Metformin has been shown to switch on an enzyme that blocks mTOR – a protein that helps tobacco-induced lung tumours grow.

The findings were so strong the team now wants to test it in smokers to see if it can keep then from developing tumours.