Hereditary breast–ovarian cancer syndrome

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Hereditary breast–ovarian cancer syndrome
Other namesHBOC
Ovarian and breast cancer patients in a pedigree chart of a family
SpecialtyObstetrics and gynaecology, endocrinology, dermatology, oncology, medical genetics Edit this on Wikidata

Hereditary breast–ovarian cancer syndromes (HBOC) are

families (either one individual had both, or several individuals in the pedigree had one or the other disease). It accounts for 90% of the hereditary cancers.[1] The hereditary factors may be proven or suspected to cause the pattern of breast and ovarian cancer occurrences in the family.[2] The name HBOC may be misleading because it implies that this genetic susceptibility to cancer is mainly in women. In reality, both sexes have the same rates of gene mutations and HBOC can predispose to other cancers including prostate cancer and pancreatic cancer.[3] For this reason, the term "King syndrome" has recently come into use. The new name references Mary-Claire King
who identified the genes BRCA1 and BRCA2.

Most hereditary breast-ovarian cancer syndromes are inherited in an autosomal dominant pattern. Biallelic and homozygous inheritance of defective alleles that confer this syndrome is usually an embryonically lethal condition; live cases usually experience a severe form of Fanconi anemia.

Causes

Absolute risk of cancers in BRCA1 or BRCA2 mutation.[4]

A number of genes are associated with HBOC.[5] The most common of the known causes of HBOC are:

  • BRCA mutations:[5] 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.[6]

Other identified genes include:

  • MLH1, MSH2, MSH6, PMS2: mutations in genes that lead to Lynch Syndrome put individuals at risk for ovarian cancer.[7]
  • 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.[5]
  • clinical signs, as well as an increased risk for many cancers.[5]
  • gastric cancer.[5]
  • STK11: Mutations produce Peutz–Jeghers syndrome. It is extremely rare, and creates a predisposition to breast cancer, intestinal cancer, and pancreatic cancer.[5]
  • colon cancer and prostate cancer.[5]
  • ataxia telangectasia; female carriers have approximately double the normal risk of developing breast cancer.[5]
  • PALB2: Studies vary in their estimate of the risk from mutations in this gene and the frequency of mutations in this gene may be different among different populations.[8] It may be moderate risk, or as high as BRCA2.[5]

For many of these genes, inheriting both defective alleles usually result in an embryonically lethal phenotype. Live cases suffer from a severe form of

Fanconi Anemia; biallelic mutations of BRCA1 lead to Fanconi anemia complementation group S, and biallelic mutations of BRCA2 lead to complementation group D1. [9]

Approximately 45% of HBOC cases involve unidentified genes, or multiple genes.[5]

Diagnosis

Prevention

People with BRCA1 and BRCA2 mutations are recommended to have a

CA-125
is also recommended.

Prophylactic

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.[6] An increasing number women who test positive for faulty BRCA1 or BRCA2 genes choose to have risk-reducing surgery. At the same time the average waiting time for undergoing the procedure is two-years which is much longer than recommended.[10][11]

References

  1. ISBN 978-1-4987-4428-7
    .
  2. ^ "Hereditary Breast Ovarian Cancer Syndrome (BRCA1 / BRCA2)". Stanford University. Retrieved 2008-09-02.
  3. PMID 31270479
    .
  4. PMID 20301425
    .
  5. ^
    ISBN 978-1-59102-776-8
    .
  6. ^
    S2CID 29024566
    .
  7. S2CID 46967266
    .
  8. ^
    PMID 31206626
    .
  9. PMID 25472942
    .
  10. doi:10.3310/alert_48318
    .
  11. S2CID 231876899
    .

External links

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