Hereditary breast–ovarian cancer syndrome
| Hereditary breast–ovarian cancer syndrome | |
|---|---|
 | |
| Ovarian and breast cancer patients in a pedigree chart of a family | |
| Specialty | Obstetrics and gynaecology, endocrinology, dermatology, oncology, medical genetics  |
Hereditary breast–ovarian cancer syndromes (HBOC) are cancer syndromes that produce higher than normal levels of breast cancer and ovarian cancer in genetically related families (either one individual had both, or several individuals in the pedigree had one or the other disease). The hereditary factors may be proven or suspected to cause the pattern of breast and ovarian cancer occurrences in the family.[1]
Causes
Approximate proportion of hereditary breast cancer cases caused by each gene
A number of genes are associated with HBOC.[2] The most common of the known causes of HBOC are:
- BRCA mutations:[2] Harmful mutations in the BRCA1 and BRCA2 genes can produce very high rates of breast and ovarian cancer, as well as increased rates of other cancers. Mutations in BRCA1 are associated with a 39-46% risk of ovarian cancer and mutations in BRCA2 are associated with a 10-27% risk of ovarian cancer.[3]
Other identified genes include:
- TP53: Mutations cause Li-Fraumeni syndrome. It produces particularly high rates of breast cancer among younger women with mutated genes, and despite being rare, 4% of women with breast cancer under age 30 have a mutation in this gene.[2]
- PTEN: Mutations cause Cowden syndrome, which produces hamartomas (benign polyps) in the colon, skin growths, and other clinical signs, as well as an increased risk for many cancers.[2]
- CDH1: Mutations are associated with lobular breast cancer and gastric cancer.[2]
- STK11: Mutations produce Peutz–Jeghers syndrome. It is extremely rare, and creates a predisposition to breast cancer, intestinal cancer, and pancreatic cancer.[2]
- CHEK2: Approximately one out of 40 northern Europeans have a mutation in this gene, making it a common mutation. Considered a moderate-risk mutation, it may double or triple the carrier's lifetime risk of breast cancer, and also increase the risk of colon cancer and prostate cancer.[2]
- ATM: Mutations cause ataxia telangectasia; female carriers have approximately double the normal risk of developing breast cancer.[2]
- PALB2: Studies vary in their estimate of the risk from mutations in this gene. It may be moderate risk, or as high as BRCA2.[2]
Approximately 45% of HBOC cases involve unidentified genes, or multiple genes.[2]
Prevention
People with BRCA1 and BRCA2 mutations are recommended to have a transvaginal ultrasound 1-2 times per year. Screening with CA-125 is also recommended. Prophylactic salpingo-oophorectomy (removal of the ovaries and Fallopian tubes to prevent cancer) is recommended at age 35-40 for people with BRCA1 mutations and at age 40-45 for people with BRCA2 mutations.[3]
References
- ^ "Hereditary Breast Ovarian Cancer Syndrome (BRCA1 / BRCA2)". Stanford University. Retrieved 2008-09-02.
- ^ a b c d e f g h i j Morris, Joi L.; Gordon, Ora K. (Ora Karp) (2010). Positive results : making the best decisions when you're at high risk for breast or ovarian cance. Amherst, N.Y.: Prometheus Books. pp. 337–340. ISBN 978-1-59102-776-8.
- ^ a b Ring, Kari L.; Garcia, Christine; Thomas, Martha H.; Modesitt, Susan C. (November 2017). "Current and future role of genetic screening in gynecologic malignancies". American Journal of Obstetrics and Gynecology. 217 (5): 512–521. doi:10.1016/j.ajog.2017.04.011. ISSN 1097-6868. PMID 28411145.