Our comprehensive risk assessment can help when breast cancer appears to run in your family. Given that 5% to 10% of breast cancers likely have hereditary causes, we can offer additional steps to protect your health or adjust your treatment. Learn more about our Cancer Genetics Program »
Genes pass along inherited information. But some missing, duplicated or miscoded genes increase risk for breast cancer, in women and men. While researchers have not identified all these genes, those we know include:
BRCA1 and BRCA2: Mutations in these genes cause up to half of hereditary breast cancer, with ties to ovarian cancer and other cancers. Approximately 65% to 70% of women with a BRCA1 mutation develop breast cancer, and approximately 45% to 50% with a BRCA2 mutation do. In women without a mutation, only 12% do. BRCA1 is more likely to cause triple-negative breast cancer, which is more challenging to treat. See our BRCA decision tool, created by Stanford doctors and scientists and used by women worldwide to weigh their options.
Other high-risk mutations: Some less common mutations can also significantly raise breast cancer risk. Some are associated with cancer syndromes that cause a variety of cancers. These mutations and syndromes include:
- CDH1 and hereditary diffuse gastric cancer
- PTEN and Cowden syndrome
- TP53 and Li-Fraumeni syndrome
Moderate-risk mutations: Mutations in ATM, PALB2, and CHEK2 genes increase breast cancer risk, but probably not by as much as the high-risk mutations do. They also slightly increase risk for other cancers, in both men and women.