Talk with Your Doctor
According to the American Cancer Society, about 5 to 10% of breast cancer cases are thought to be hereditary, meaning that they result from gene defects (called mutations) inherited from a parent.
The most common cause of hereditary breast cancer is an inherited mutation in the BRCA1 and BRCA2 genes. In normal cells, these genes help prevent cancer by making proteins that ehlp keep the cells from growing abnormally. If you have inherited a mutated copy of either gene from a parent, you have a high risk of developing breast cancer during your lifetime.
Although in some families with BRCA1 mutations the lifetime risk of breast cancer is as high as 80%, on average this risk seems to be in the range of 55 to 65%. For BRCA2 mutations the risk is lower, around 45%.
Breast cancers linked to these mutations occur more often in younger women, and more often affect both breasts, compared with cancers not linked to these mutations. Women with these inherited mutations also have an increased risk for developing other cancers, particularly ovarian cancer.
If breast cancer runs in your family, talk with your doctor about what additional testing might be appropriate.
–Source: American Cancer Society