Breast Cancer And Genetic Testing
At the current time, testing is available for BRCA gene mutations, as well as mutations ATM, CDH1, CHEK2, MRE11A, MSH6, NBN, PALB2, PMS2, PTEN, RAD50, RAD51C, SEC23B, and TP53, with this area expected to expand dramatically in the near future.
Having these tests available, however, raises many questions. For example, who might have hereditary breast cancer and who should be tested? What should you do if you test positive for one of these genes?
Ideally, any testing should be done only with the guidance and help of a genetic counselor. There are two reasons for this.
One is that it can be devastating to learn that you carry a mutation that may increase your risk, and the guidance of someone who is aware of recommended management and screening is invaluable.
As noted earlier, some mutations confer a high risk and others a much lower risk. Some mutations might be of more concern earlier in life , whereas others might not require early screening. A genetic counselor can help you learn about what is currently recommended with regard to screening for your particular mutation while taking into account any other risk factors you might have.
The other reason genetic counseling is so important is that you may have a significant risk of developing breast cancer even if your tests are negative. There is much yet to learn, and a genetic counselor can help you look at your family history to see if you may carry a high risk despite negative testing, and plan screening accordingly.
Other Cancer Risks For People With Hboc
Anyone with mutations in the BRCA2 gene may be at an increased risk of other types of cancer, including melanoma and pancreatic, stomach, esophageal, and bile duct cancers.Mutations in other genes may be associated with an increased risk of developing breast and other cancers, including the Li-Fraumeni syndrome , Cowden syndrome, and others. The pattern of cancers in the family is often a clue to the specific gene that may explain the hereditary cancer for that family. Multigene panels are available for people with a strong personal and family history of cancer. Multigene panel tests include BRCA1 and BRCA2 and many other genes that increase the risk of breast, ovarian, and other cancers. If your BRCA1 and BRCA2 test was negative, then you may or may not have mutations in other genes. A newer type of testing, called next generation sequencing, massively parallel sequencing, or deep sequencing, has made testing for multiple genes at the same time faster and less expensive. If a genetic mutation is found, this could explain the cancers in a specific family and provide information about who is at risk and the appropriate types of monitoring and prevention/risk reduction methods.
Having Dense Breast Tissue
Breasts are made up of fatty tissue, fibrous tissue, and glandular tissue. Breasts appear denser on a mammogram when they have more glandular and fibrous tissue and less fatty tissue. Women with dense breasts on mammogram have a risk of breast cancer that is about 1 1/2 to 2 times that of women with average breast density. Unfortunately, dense breast tissue can also make it harder to see cancers on mammograms.
A number of factors can affect breast density, such as age, menopausal status, the use of certain drugs , pregnancy, and genetics.
To learn more, see our information on breast density and mammograms.
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Support For Hereditary Breast Cancer
Just as people who have been diagnosed with breast cancer need support, those who carry genes that increase risk need support. Fortunately, there are organizations that focus specifically on supporting people in this situation.
One organization, FORCE, which is an acronym for Facing Our Risk of Cancer Empowered, offers a helpline, message board, and information for those who are facing hereditary cancer.
Other organizations and support communities are available to help people cope with the decisions related to a diagnosis of hereditary breast cancer.
The term “previvor” was coined by FORCE to describe people who are surviving a predisposition to breast cancer. If this is the situation you are facing, you are not alone, and using the hashtag #previvor, you can find many others on Twitter and other social media outlets.
How Much Does An Inherited Harmful Variant In Brca1 Or Brca2 Increase A Womans Risk Of Breast And Ovarian Cancer
A womans lifetime risk of developing breast and/or ovarian cancer is markedly increased if she inherits a harmful variant in BRCA1 or BRCA2, but the degree of increase varies depending on the mutation.
Breast cancer: About 13% of women in the general population will develop breast cancer sometime during their lives . By contrast, 55%72% of women who inherit a harmful BRCA1 variant and 45%69% of women who inherit a harmful BRCA2 variant will develop breast cancer by 7080 years of age . The risk for any one woman depends on a number of factors, some of which have not been fully characterized.
Like women with breast cancer in general, those with harmful BRCA1 or BRCA2 variants also have an increased risk of developing cancer in the opposite breast in the years following a breast cancer diagnosis . The risk of contralateral breast cancer increases with the time since a first breast cancer, reaching 20%30% at 10 years of follow-up and 40%50% at 20 years, depending on the gene involved.
Ovarian cancer: About 1.2% of women in the general population will develop ovarian cancer sometime during their lives . By contrast, 39%44% of women who inherit a harmful BRCA1 variant and 11%17% of women who inherit a harmful BRCA2 variant will develop ovarian cancer by 7080 years of age .
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What Are The Benefits Of Genetic Testing For Brca1 And Brca2 Variants
There can be benefits to genetic testing, regardless of whether a person receives a positive or a negative result.
The potential benefits of a true negative result include a sense of relief regarding the future risk of cancer, learning that one’s children are not at risk of inheriting the family’s cancer susceptibility, and the possibility that special check-ups, tests, or risk-reducing surgeries may not be needed.
A positive test result may allow people to make informed decisions about their future health care, including taking steps to reduce their cancer risk.
Guidelines For Elective Surgical Options
Women with BRCA1 or BRCA2 mutations face a significant risk of breast and ovarian cancer. Prophylactic removal of the fallopian tubes and ovaries is recommended by about age 40. Many women with BRCA1 or BRCA2 mutations will also elect to have their breasts removed. Nipple-sparing mastectomy is an effective option for these women.
Making the decision to have an elective preventive double mastectomy and removal of the ovaries is personal and should be based on many life factors. You must balance where you are in your childbearing years, what your future choices may be, and whether you would prefer to follow a rigorous screening schedule instead of making such a life-altering choice.
Whatever your decision, we encourage you to make an informed choice. If you do elect to have a preventive double mastectomy, our breast specialists will guide you in the appropriate breast surgery reconstruction to help restore your body image after treatment.
If you are interested in discussing ovary removal surgery , we will refer you to one of our gynecological oncologists.
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Tests For Brca And Other Gene Mutations
A genetic test can tell you if you have any mutations in genes that are related to an increased risk of breast cancer. Its important to know that genetic testing is most helpful when you have a strong family history of either breast or ovarian cancer or a personal history of breast cancer.
If youd like to be tested, contact your doctor or your hospitals education office. Ask for a recommendation for a genetic counselor. Make an appointment and discuss the risks of undergoing genetic testing.
Your genes may affect your risk for breast cancer, but your lifestyle can have an impact as well. Whether or not you have a genetic mutation, its important to lower your risk whenever you can.
The following preventive measures may help you avoid a breast cancer diagnosis.
Familial Atypical Multiple Mole Melanoma Syndrome
Researchers have found that familial atypical multiple mole melanoma syndrome increases the risk of developing melanoma. People who have FAMMM have more than 50 moles and at least one close relative has been diagnosed with a melanoma. A close relative is a parent, brother, sister, child, aunt, uncle or grandparent. Some families with FAMMM are also at a higher risk of developing pancreatic cancer.
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What To Do If You’re Worried
Speak to a GP if cancer runs in your family and you’re worried you may get it too. They may refer you to a local genetics service for an NHS genetic test, which will tell you if you have inherited one of the cancer risk genes.
This type of testing is known as predictive genetic testing. It’s “predictive” because a positive result means you have a greatly increased risk of developing cancer. It does not mean you have cancer or are definitely going to develop it.
You may be eligible for this NHS test if the faulty gene has already been identified in one of your relatives, or if there is a strong family history of cancer in your family.
How Do I Get Tested For An Inherited Cancer Syndrome
Diagnosing an inherited cancer syndrome before or after cancer develops requires a combination of family history, genetic counseling, genetic testing, and laboratory testing. A genetic counselor or clinical geneticist can help you decide if genetic testing would be useful for you.
Genetic tests can be performed on a sample of fresh blood or on preserved tissue that was previously taken in a biopsy or surgery. Testing techniques can vary, and the technology is evolving rapidly. Some detailed laboratory testing can even be done years after an initial cancer diagnosis.
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Inheriting Certain Gene Changes
About 5% to 10% of breast cancer cases are thought to be hereditary, meaning that they result directly from gene changes passed on from a parent.
BRCA1 and BRCA2: The most common cause of hereditary breast cancer is an inherited mutation in the BRCA1 or BRCA2 gene. In normal cells, these genes help make proteins that repair damaged DNA. Mutated versions of these genes can lead to abnormal cell growth, which can lead to cancer.
- If you have inherited a mutated copy of either gene from a parent, you have a higher risk of breast cancer.
- On average, a woman with a BRCA1 or BRCA2 gene mutation has up to a 7 in 10 chance of getting breast cancer by age 80. This risk is also affected by how many other family members have had breast cancer.
- Women with one of these mutations are more likely to be diagnosed with breast cancer at a younger age, as well as to have cancer in both breasts.
- Women with one of these gene changes also have a higher risk of developing ovarian cancer and some other cancers.
- In the United States, BRCA mutations are more common in Jewish people of Ashkenazi origin than in other racial and ethnic groups, but anyone can have them.
Other genes: Other gene mutations can also lead to inherited breast cancers. These gene mutations are much less common, and most of them do not increase the risk of breast cancer as much as the BRCA genes.
Mutations in several other genes have also been linked to breast cancer, but these account for only a small number of cases.
How Can Genes Cause Cancer
Inside almost every single cell in your body is a structure called nucleus. The nucleus is the control centre of the cell. Inside the nucleus are 23 pairs of chromosomes made up of genes. Genes are coded messages that tell cells how to behave. They control how our bodies grow and develop. We each have about 25,000 genes.
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Questions To Ask The Health Care Team
If you are concerned about your risk of cancer, talk with your health care team. It can be helpful to bring someone along to your appointments to take notes. Consider asking your health care team the following questions:
What is my risk of developing breast cancer and ovarian cancer?
What is my risk for other types of cancer?
What can I do to reduce my risk of cancer?
What are my options for cancer screening?
If you are concerned about your family history and think your family may have HBOC, consider asking the following questions:
Does my family history increase my risk of breast cancer, ovarian cancer, or other types of cancer?
Should I meet with a genetic counselor?
Should I consider genetic testing?
Is Breast Cancer A Genetic Disease
Yes, some breast cancers occur as a result of inheriting genes that contain certain mutations. But, hereditary breast cancer accounts for only 5 to 10% of all breast cancer diagnoses. Among these diagnoses, a family may have one of these inherited gene mutations or genetic conditions that increase their cancer risk:
- BRCA1 or BRCA2. Mutations of these genes are related to an increased risk for breast and ovarian cancer
- Li-Fraumeni Syndrome is caused by mutations in the TP53 gene
- Cowden Syndrome caused by mutations in the PTEN gene
- ATM, CHEK2, PALB2. Mutations in these genes are associated with a moderately increased risk for breast cancer
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What Is Hereditary Breast And Ovarian Cancer
A diagnosis of Hereditary Breast and Ovarian Cancer Syndrome 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:
1 or more women are diagnosed at age 45 or younger
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 fathers side both diagnosed with these cancers
A woman is diagnosed with a second breast cancer in the same or the other breast or has both breast and ovarian cancers
A male relative is diagnosed with breast cancer
There is a history of breast cancer, ovarian cancer, prostate cancer, and/or pancreatic cancer on the same side of the family
Having Ashkenazi Jewish ancestry
Breast Cancer Genes And Inheritance
Breast cancer is the most common cancer that affects women in the United States. There are at least two majors genes that when they mutate can causebreast cancer. These genes can be passed from parent to child, increasing the risk ofdeveloping cancer in those child that have parent carrying these genes. BRCA1 and BRCA2genes are located on chromosome 17 and chromosome 13 respectively. There is a 90% chance of developing breast cancer for a woman that has these mutated genes. In contrast,men carrying BRCA1 have no risk to develop breast cancer, but those carrying BRCA2 geneshave high risk. It is important to note that mutations in these genes can be passed on tochildren by either parent. A man with a mutation is just as likely to pass this gene to hischildren as a woman with a mutation. Hereditary cancer occurs at young age, for instance awoman in her 20’s with breast cancer is more likely to have hereditary type of cancer that awoman in her 50’s.
BRCA1 and BRCA2 are tumor suppressor genes, these genes also called “Anti-Oncogenes” which normally are involved in regulating cell growth, the proteins inhibit theproliferation of cell, which is crucial for the normal cell development and differentiation. .
The second similarity is that both BRCA1 and BRCA2 bind to Rad5 protein that isinvolved in maintain the integrity of the genome .
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Medullary Thyroid Cancer And Related Syndromes
Medullary thyroid cancer is a rare type of thyroid cancer. Between 3 and 10 out of every 100 thyroid cancers are this type. About a quarter of medullary thyroid cancers are caused by an inherited faulty gene which runs in the family.
Faulty genes may cause medullary thyroid cancer as part of rare syndromes called multiple endocrine neoplasia or MEN for short. The types of MEN that cause thyroid cancer are MEN2a and MEN2b.
People with MEN2a are also at higher risk of developing a rare type of cancer of the adrenal gland and overactive parathyroid glands. People with MEN2b are at higher risk of getting adrenal cancer and small growths on their tongue and lips.
If 4 or more members of a family have a medullary thyroid cancer but dont have any other cancer or a condition that may be linked to MEN, doctors usually diagnose it as familial medullary thyroid cancer .
Read about MEN and thyroid cancer in our information about thyroid cancer risks and causes.
Brca1 And Brca2 Genes
In 1990, DNA linkage studies on large families with the above characteristics identified the first gene associated with breast cancer. Scientists named this gene breast cancer 1 or BRCA1 . BRCA1 is located on chromosome 17. Mutations in the gene are transmitted in an autosomal dominant pattern in a family.
Since it was clear that not all breast cancer families were linked to BRCA1, studies continued and in 1994, scientists discovered another gene , and named it BRCA2. BRCA2 is located on chromosome 13. Mutations in this gene are also transmitted in an autosomal dominant pattern in a family.
Both BRCA1 and BRCA2 are tumor suppressor genes that usually have the job of controlling cell growth and cell death. Everyone has two BRCA1 and two BRCA2 genes . When a person has one altered or mutated copy of either the BRCA1 or BRCA2 gene, their risk for various types of cancer increases.
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