Breast cancer is the most common cancer in the UK. The lifetime risk of a woman developing breast cancer is 1 in 8. The majority of breast cancers (81%) occur in women over the age of 50. Exactly why some people get breast cancer and some don't is not fully understood. Research suggests that breast cancer is caused by a combination of lots of different factors, many of which are beyond our control.
Most breast cancers happen by chance but a small number of people diagnosed with breast cancer (5%) have inherited a fault in one of the known breast cancer genes; BRCA1, BRCA2 or TP53.