Familial breast cancer is important because of all the known risk factors associated with developing the disease. The one with the most predictability is a positive family history. It is also important because a family history causes anxiety in the families concerned, and young women will often ask their chance of developing the disease. This form of breast cancer accounts for 10% of causes and has factors that distinguish it from the sporadic variety. Relatives of familial breast cancer patients are not only at an increased risk of developing the disease (if female) but also of developing other tumours especially colonic.