Beyond the BRCA Genes
Hester Hill Schnipper, LICSW, OSW-C Program Manager, Oncology Social Work
MARCH 19, 2018
Since 1994, testing for the BRCA1 and BRCA2 genes has been available for people with family histories of breast and/or ovarian cancer. Sometimes referred to as the Jewish Gene, because of the higher incidence among Ashkanazi Jews, these mutations actually occur in people all over the world with or without any Ashkanazi heritage. Testing positive for one does not guarantee that the individual will sometime develop breast or ovarian cancer, but it highly increases the likelihood of an eventual diagnosis. At this point, many women who are diagnosed with breast or ovarian cancer undergo gene testing (a blood test) and others who are at high risk, but have not yet been diagnosed, do the same.
Over the years, more sophisticated genetic screening tests have been developed and are sometimes recommended for individuals with a strong family history. Clustered under the umbrella of HBOC (hereditary breast and ovarian cancer), these tests can identify mutations that may increase the risk of other cancers, too. Although commercial companies are now offering at-home tests for the BRCA genes, I strongly feel that these are conversations and tests that should only happen with a genetic counselor who works closely with a physician genetic risk specialist. There are too many possible questions and complications and decisions to safely manage this on your own.
From CancerNet comes this report:
Hereditary Breast and Ovarian Cancer
A diagnosis of Hereditary Breast and Ovarian Cancer Syndrome (HBOC) is considered when there are multiple cases of breast cancer and/or ovarian cancer on the same side of the family. The chance that a family has HBOC increases in any of these situations:
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1 or more women are diagnosed at age 45 or younger
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1 or more women are diagnosed with breast cancer before age 50 with additional family history of cancer, such as prostate cancer, melanoma, and pancreatic cancer
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There are breast and/or ovarian cancers in multiple generations on the same side of the family, such as having both a grandmother and an aunt on the father’s side both diagnosed with these cancers
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A woman is diagnosed with a second breast cancer in the same or the other breast or has both breast and ovarian cancers
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A male relative is diagnosed with breast cancer
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There is a history of breast cancer, ovarian cancer and/or pancreatic cancer on the same side of the family
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There is a history of breast and/or ovarian, pancreatic, or male breast cancer in a family of Ashkenazi Jewish ancestry
What causes HBOC?
HBOC is an inherited genetic condition. This means that the cancer risk is passed from generation to generation in a family. 2 genes are associated with the majority of HBOC families: BRCA1 and BRCA2. BRCA stands for BReast CAncer. Other, less common genes have also been associated with an increased risk of developing breast and other cancers, such as mutations in the TP53, PTEN, CDH1, ATM, CHEK2 or PALB2 tumor suppression genes and many others. Blood tests now include many of these genes in a single, multiple-gene panel test. A mutation (alteration) in either BRCA1 or BRCA2 gives a woman an increased lifetime risk of developing breast and ovarian cancers. Men with these gene mutations also have an increased risk of breast cancer and prostate cancer. There is a slight increase in the risk of other cancers including pancreatic cancer and melanoma among carriers of BRCA1 or BRCA2 mutations. Not all families with multiple cases of breast and ovarian cancer have mutations in BRCA1 or BRCA2.
How is HBOC inherited?
Normally, every cell has 2 copies of each gene: 1 inherited from the mother and 1 inherited from the father. HBOC follows an autosomal dominant inheritance pattern, in which a mutation needs to happen in only 1 copy of the gene for the person to have an increased risk of getting that disease. This means that a parent with a gene mutation may pass along a copy of their normal gene or a copy of the gene with the mutation. Therefore, a child who has a parent with a mutation has a 50% chance of inheriting that mutation. A brother, sister, or parent of a person who has a mutation also has a 50% chance of having inherited the same mutation.
Options exist for people interested in having a child when they know that 1 prospective parent carries a gene mutation that increases the risk for this or any other hereditary cancer syndrome. Preimplantation genetic diagnosis (PGD) is a medical procedure done in conjunction with in-vitro fertilization (IVF). It allows both women and men who carry a specific, known genetic mutation to have children who do not carry the mutation. A woman’s eggs are removed and then fertilized (in a laboratory setting) with sperm. When the embryos are only 8 cells in size (very early in the development process), 1 cell is removed and is tested for the hereditary condition in question. The future parent(s) can then choose to transfer the embryos without the mutation to the woman’s uterus. PGD has been in use for over a decade, and more recently has been used for several hereditary cancer predisposition syndromes. However, this is a complex procedure with financial, physical, and emotional factors to consider before starting. For more information, talk with an assisted reproduction specialist at a fertility clinic.