Family history. A woman's risk of breast cancer increases if her mother, sister, daughter, or two or more other close relatives, such as cousins, have a history of breast cancer, especially if they were diagnosed with breast cancer at age 50 or younger.
A small number of women who have a family history of breast cancer have inherited changes to certain genes, such as BRCA1 or BRCA2, that increase their breast cancer risk.
Genetic tests are available to find out if you have the genetic mutations long before any cancer appears.
Breast Cancer Risk: Should I Have a BRCA Gene Test?