BRCA1, familial breast-ovarian cancer susceptibility 1
What are the main symptoms of Hereditary Breast and Ovarian Cancer syndrome?
The main symptom or feature of Hereditary Breast and Ovarian Cancer syndrome is an increased risk to develop cancer. The risks are highest for female breast cancer and ovarian cancer. The chance for a woman with a BRCA1 mutation to develop breast cancer by age 70 is between 55% and 65%. The chance for a woman with a BRCA1 mutation to develop ovarian cancer by age 70 is 39%. Men also have an increased risk to develop breast cancer and prostate cancer. More specifically, men with a BRCA1 mutation have a 1.2% risk to develop breast cancer by age 70. Both men and women also have an increased risk for pancreatic cancer.
Multiple studies have been done to estimate cancer risks in men and women with BRCA1 gene mutations. Therefore risk numbers may vary somewhat and these estimates may change over time as more information is learned about BRCA1-associated cancer risks. Talk to a genetic counselor or other medical professional with expertise in HBOC to learn more about BRCA1-associated cancer risks. Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
- Chen, S and Parmigiani, G. Meta-Analysis of BRCA1 and BRCA2 Penetrance. J Clin Oncol. 2007; 25: 11: 1329-1333
- Tai YC, Domchek S, Parmigiani G, et al. Breast cancer risk among male BRCA1 and BRCA2 mutation carriers. J Natl Cancer Inst. 2007;99:1811-1814.
- Antoniou A, Pharoah PDP, Narod S, et al. Average risks of breast and ovarian cancer associated with BRCA1 or BRCA2 mutations detected in case series unselected for family history: a combined analysis of 22 studies. Am J Hum Genet. 2003;72:1117-1130.
More Symptoms Content
What kind of family history is suspicious for Hereditary Breast and Ovarian Cancer syndrome?
Families that have multiple diagnoses of breast and/or ovarian cancers may have Hereditary Breast and Ovarian Cancer (HBOC) syndrome due to a change in the BRCA1 gene. Pancreatic cancer and prostate cancer are also found in families with BRCA1 gene mutations. Cancer diagnoses tend to occur at younger ages in individuals with a BRCA1 gene change. A diagnosis of breast cancer under age 50 is considered to be younger than expected in the general population. A diagnosis of breast cancer in a male, individuals with multiple BRCA1-associated cancers, and cancer in multiple generations on the same side of the family also increase the suspicion that there could be a mutation in the BRCA1 gene.
A genetic counselor can review a family history of cancer and help someone understand if their family may have a gene change causing HBOC. Genetic counselors in the United States can be found on the National Society of Genetic Counselors website. Genetic counselors in Canada can be found at the Canadian Association of Genetic Counselors website.
Is there one or two characteristic "odd" or "unusual" symptom or clinical feature of Hereditary Breast and Ovarian Cancer syndrome?
There are some findings in a personal and family history that can be considered red flags of Hereditary Breast and Ovarian Cancer (HBOC) syndrome.
- Breast cancer diagnosed at a young age
- Male breast cancer
- Ovarian cancer
- Triple negative breast cancer
- Bilateral breast cancer
- Multiple generations affected with cancer
- Ashkenazi Jewish ancestry
Is there variable expression or incomplete penetrance in Hereditary Breast and Ovarian Cancer syndrome?
Not every person with Hereditary Breast and Ovarian Cancer (HBOC) syndrome will develop cancer in his or her lifetime. In other words, HBOC syndrome is not completely penetrant. This condition also has variable expression, which means that not every person who develops cancer will develop the same type of cancer. Knowing there is an increased risk for developing certain types of cancer will help healthcare providers offer appropriate screening and risk reduction options.