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Hereditary Breast and Ovarian Cancer (HBOC) Syndrome

Hereditary breast and ovarian cancer (HBOC) is primarily associated with mutations in BRCA1 or BRCA2 genes. Mutations in other genes are associated with HBOC, but are less common. BRCA gene mutations can be inherited from either the mother or father, and only one copy of the mutation is needed to be at risk.

One in 40 Ashkenazi Jews has a disease-causing BRCA gene mutation, compared to one in 300 to 500 individuals in the general United States population. Individuals with HBOC are more likely to get breast, ovarian, pancreatic, prostate, and skin (melanoma) cancers. About 5% to 10% of breast cancers and 10% to 15% of ovarian cancers are due to HBOC.

HBOC syndrome is associated with an increased risk of—

  • Early-onset breast cancer.
  • Triple-negative breast cancer (estrogen receptor, progesterone receptor, and Her2/neu negative).
  • Bilateral breast cancer.
  • Ovarian cancer at any age.
  • Prostate cancer.
  • Pancreatic cancer.
  • Melanoma.
  • A second primary cancer.
  • Cancer recurrence.

The absolute cancer risks (up to age 70) for individuals with HBOC are—1 2 3 4

  • Breast cancer: 46% to 71% in females, and up to 2.8% in males (in other words, between 46% and 71% of women and up to 2.8% of men with HBOC may develop breast cancer).
  • Ovarian cancer: 17% to 46%.
  • Prostate cancer: Up to 7.5%.
  • Pancreatic cancer: 1% to 7%.
  • Melanoma: 0.1% to 2.4%.


1National Coalition for Health Professional Education in Genetics. Hereditary breast and ovarian cancer fact sheet.

2American Cancer Society. What are the key statistics about melanoma skin cancer?

3United States Preventive Services Task Force (USPSTF). BRCA-Related Cancer: Risk Assessment, Genetic Counseling, and Genetic Testing.

4National Comprehensive Cancer Network. NCCN Guidelines: Genetic/Familial High-Risk Assessment: Breast and Ovarian [PDF-1.1MB] Note: Login required to access.

Knowledge Check

Answer the question on your own and check your answer.

A patient who has mutations in the BRCA 1/2 genes is at an increased risk of developing which cancers? Check Answer

Answer: Breast, ovarian, prostate, and pancreatic cancers, and melanoma.