Women who are at increased risk of developing breast cancer may be able to take chemoprevention drugs to reduce their risk. However, these drugs only prevent a third of breast cancers, the side effects can be harsh, and there’s only one drug available for pre-menopausal women.

We know that our genetics play a key role in determining breast cancer risk, but we need to know much more about the specific genes involved and how they affect an individual person’s risk.