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What Type Of Breast Cancer Is Genetic

How Is Hboc Inherited

Understanding the genetic risks of breast cancer

Normally, each person has 2 copies of each gene in their bodys cells: 1 copy is inherited from a persons mother and 1 copy is inherited from a persons father. HBOC follows an autosomal dominant inheritance pattern. This means that 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 sibling or parent of a person who has a mutation also has a 50% chance of having inherited the same mutation. However, if the parents test negative for the mutation , the risk to the siblings significantly decreases but their risk may still be higher than an average risk.

Pten And Cowden Syndrome

Cowden syndrome is a rare autosomal dominant predisposition to both benign and malignant neoplasms. Breast cancer develops in 20%30% of carrier women. Other tumors seen among patients with Cowden syndrome include adenomas and follicular cell carcinomas of the thyroid gland, polyps and adenocarcinomas of the gastrointestinal tract, and ovarian cysts and carcinoma . Cowden syndrome is caused by germline mutations in the PTEN gene . PTEN, a tumor suppressor gene on 10q23.3 , is a dual-specificity phosphatase .

Genetic Counseling And Testing For Breast Cancer Risk

Some people inherit changes in certain genes that increase their risk of breast cancer . Genetic testing can look for mutations in some of these genes. While it can be helpful in some cases, not everyone needs to be tested, and each person should carefully consider the pros and cons of testing. Its very important to understand what genetic testing can and cant tell you before these tests are done.

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Does Health Insurance Cover The Cost Of Genetic Testing For Brca1 And Brca2 Variants

People considering BRCA1 and BRCA2 variant testing may want to confirm their insurance coverage for genetic counseling and testing. Genetic counselors can often help answer questions about insurance coverage for genetic testing.

Some genetic testing companies may offer testing for inherited BRCA1 and BRCA2 variants at no charge to patients who lack insurance and meet specific financial and medical criteria.

Worried About Your Breast Cancer Risk

Breast Cancer Signs Run in the Family

Does breast cancer seem to run in your family? Have you had abnormal mammograms before? Roswell Parks High Risk Breast Cancer Program can help. Our team of specialists will assess your personal risk for breast cancer, based on your familys cancer history, your personal medical history, possible genetic mutations and more, and then provide you with a path forward for ongoing exams, surveillance, and preventive options.

Dont live in fear of your breast cancer risk. Let us help you learn your personal breast cancer risk and what you can do about it and leave the worry behind.

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How Your Test Results Can Help You

A positive result for breast cancer genes can be difficult to deal with. But you can use this information to your advantage.

If we know you have a breast cancer gene alteration, we can take extra steps to catch cancer early, when its most treatable, Dr. Eng says. Your providers can perform enhanced screenings starting at an early age, usually 25 or 30, depending on the gene. Knowledge is power.

Breast Cancer Screening Recommendations For Men

Screening for breast cancer in men has not been sufficiently studied to determine efficacy. A breast exam could be a useful screening tool for men with BRCA mutations or a strong family history of breast cancer. Men who are at high risk for breast cancer should discuss options with their healthcare provider.

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What Are The Estimated Cancer Risks Associated With Hboc

Cancer risks for women with HBOC

  • Lifetime risk of breast cancer 45% to 75%

  • Lifetime risk of ovarian cancer

    • BRCA1 gene mutation 25% to 40%

    • BRCA2 gene mutation 10% to 20%

  • Developing a second breast cancer 20% to 40%

Cancer risks for men with HBOC

  • Lifetime risk of breast cancer

    • BRCA1 gene mutation 1% to 2%

    • BRCA2 gene mutation 6%

    • BRCA1 gene mutation some increased risk

    • BRCA2 gene mutation 20%

  • Men with a BRCA2 gene mutation have a significantly increased risk of developing more aggressive prostate cancer before age 65 and therefore screening should begin at age 40.

Common Breast Cancer Mutations

What is Hereditary Breast and Ovarian Cancer Syndrome?

Researchers have identified several key gene changes linked to breast cancer. Some of these pose a high risk, while others seem to be less significant.

BRCA1 and BRCA2

The BRCA1 and BRCA2 inherited gene mutations are the most common cause of hereditary breast cancer. Mistakes in these genes account for up to 10% of all breast cancers. BRCA mutations also raise your chances for ovarian cancer, pancreatic cancer, and, in men, prostate cancer. A BRCA mutation may raise your chances of colon cancer. Women with a BRCA1 or BRCA2 mutation have up to a 72% chance of breast cancer during their lifetime.

PALB2

Normally, the PALB2 gene makes a protein that works with the BRCA2 gene protein to repair damaged DNA and stop tumor growth. But defects in the gene can lead to a higher likelihood of breast cancer. Some studies suggest that women with a PALB2 mutation have a 14% chance of breast cancer by age 50 and a 35% chance by age 70.

PIK3CA

HER2

The HER2 gene makes a protein called HER2 . This protein is found on the surface of all breast cells and that helps them grow. If the HER2 gene malfunctions and makes too many copies of itself, it tells cells to make too much HER2 protein. This causes the cells to grow out of control.

PTEN

TP53

CDH1

Researchers have discovered many other genes related to breast cancer.

Changes in the following genes may also raise your chances:

  • BARD1

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Who Should Consider Genetic Counseling And Testing For Brca1 And Brca2 Variants

Anyone who is concerned about the possibility that they may have a harmful variant in the BRCA1 or BRCA2 gene should discuss their concerns with their health care provider or a genetic counselor.

Tests are available to see if someone has inherited a harmful variant in BRCA1 and BRCA2. However, testing is not currently recommended for the general public. Instead, expert groups recommend that testing be focused on those who have a higher likelihood of carrying a harmful BRCA1 or BRCA2 variant, such as those who have a family history of certain cancers. Testing can be appropriate for both people without cancer as well as people who have been diagnosed with cancer. If someone knows they have a mutation in one of these genes, they can take steps to reduce their risk or detect cancer early. And if they have cancer, the information about their mutation may be important for selecting treatment.

Before testing is done, a person will usually have a risk assessment, in which they meet with a genetic counselor or other health care provider to review factors such as which of their relatives had cancer, what cancers they had, and at what ages they were diagnosed. If this assessment suggests that someone has an increased risk of carrying a harmful BRCA1 or BRCA2 gene variant, their genetic counselor can discuss the benefits and harms of testing with them and order the appropriate genetic test, if the individual decides to have genetic testing .

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.

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Environmental And Lifestyle Risk Factors

Most breast cancers are related to female hormones, and therefore any factor that increases exposure to these hormones is a potential risk factor. In particular, reproductive factors associated with increased exposure to endogenous estrogens produced by the ovaries, such as earlier menarche, late menopause, low parity, and late age at first birth, are recognized breast cancer risk factors . Similarly, women exposed to exogenous hormones are often at increased risk .

Lifestyle factors are also associated with breast cancer. There is an estimated 10% increase in risk per 10 g of ethanol consumed every day . Being overweight or obese is also associated with breast cancer risk, but only in postmenopausal women, with a gain of 5 kg/m2 in body mass index resulting in an 8% increase in disease risk . On the contrary, excess weight is associated with a decrease in risk in premenopausal women. Again, these associations can be explained by hormonal factors: alcohol consumption and postmenopausal obesity are related to higher circulating estrogen levels . In postmenopause, elevated estrogen levels are most probably due to extraglandular production in the adipose tissue, whereas in premenopause, the decrease in female hormone synthesis associated with anovulatory cycles in obese women likely explains the inverse association with breast cancer .

What Other Cancers Are Linked To Harmful Variants In Brca1 And Brca2

Breast Cancer (Hereditary Factors)

Harmful variants in BRCA1 and BRCA2 increase the risk of several additional cancers. In women, these include fallopian tube cancer and primary peritoneal cancer , both of which start in the same cells as the most common type of ovarian cancer. Men with BRCA2 variants, and to a lesser extent BRCA1 variants, are also at increased risk of breast cancer and prostate cancer . Both men and women with harmful BRCA1 or BRCA2 variants are at increased risk of pancreatic cancer, although the risk increase is low .

In addition, certain variants in BRCA1 and BRCA2 can cause subtypes of Fanconi anemia, a rare syndrome that is associated with childhood solid tumors and development of acute myeloid leukemia . The mutations that cause these Fanconi anemia subtypes have a milder effect on protein function than the mutations that cause breast and ovarian cancer. Children who inherit one of these variants from each parent will develop Fanconi anemia.

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Brca1 And Brca2 Genes

Everyone has BRCA1 and BRCA2 genes. BRCA stands for BReast CAncer gene. They are important genes that stop the cells in our body from growing and dividing out of control. Doctors call these tumour suppressor genes.

A fault in the BRCA1 or BRCA2 gene means that the cells can grow out of control. This can lead to cancer developing.

Faulty BRCA1 and BRCA2 genes are rare. Only around 1 in every 400 people have a faulty BRCA1 or BRCA2 gene.

Both men and women can have a faulty BRCA1 or BRCA2 genes. People who inherit faulty versions of these genes have an increased risk of developing different types of cancers. This includes:

  • breast cancer

  • pancreatic cancer

How Genetic Testing Is Done

Genetic testing can be done on samples of blood or saliva, or from a swab of the inside of a cheek. The samples are sent to a lab for testing.

There are many different possible mutations in the BRCA genes. Testing can look for one specific mutation, or more extensive testing can be done to look for many different BRCA mutations. For example, if someone is being tested because they have a family member with a known BRCA mutation, testing might focus only on that specific mutation. In people of Ashkenazi Jewish descent, testing might focus on the specific BRCA mutations that are most common in this group of people. But if theres no reason to suspect a specific gene change, testing will likely look for many different BRCA mutations. Depending on the situation, testing might be done to look for changes in other genes as well.

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Genetic Breast Cancer Testing Recommendations

Some inherited genes can mutate and increase the risk of breast cancer. The most important of these genes are BRCA1 and BRCA2. Genetic testing can find mutations in these genes and may be recommended for people with:

  • A known family history of a BRCA mutation
  • A family history of breast cancer at a young age
  • Ashkenazi Jewish decent
  • Women diagnosed with breast cancer at a young age , regardless of family history

Not every woman needs to be tested. A healthcare provider will be able to advise whether genetic testing would be appropriate.

Brca1 And Brca2 Genetic Mutations

Abnormal gene mutation increases risk of breast cancer

Most inherited cases of breast cancer are associated with mutations in two genes: BRCA1 and BRCA2 .

Everyone has BRCA1 and BRCA2 genes. The function of the BRCA genes is to repair cell damage and keep breast, ovarian, and other cells growing normally. But when these genes contain mutations that are passed from generation to generation, the genes don’t function normally and breast, ovarian, and other cancer risk increases. BRCA1 and BRCA2 mutations may account for up to 10% of all breast cancers, or 1 out of every 10 cases.

Having a BRCA1 or BRCA2 mutation doesn’t mean you will be diagnosed with breast cancer. Researchers are learning that other mutations in pieces of chromosomes called SNPs may be linked to higher breast cancer risk in women with a BRCA1 mutation as well as women who didn’t inherit a breast cancer gene mutation.

Women who are diagnosed with breast cancer and have a BRCA1 or BRCA2 mutation often have a family history of breast cancer, ovarian cancer, and other cancers. Still, most people who develop breast cancer did not inherit a genetic mutation linked to breast cancer and have no family history of the disease.

You are substantially more likely to have a genetic mutation linked to breast cancer if:

If one family member has a genetic mutation linked to breast cancer, it does not mean that all family members will have it.

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Brca1 And Brca2 Gene Mutations

When it comes to breast cancer risk, the most important inherited gene changes are in the BRCA1 and BRCA2 genes. Women with one of these gene changes are said to have Hereditary Breast and Ovarian Cancer syndrome.

  • Women with a BRCA gene change have a greatly increased risk of breast cancer, as well as an increased risk of ovarian cancer, pancreatic cancer, and possibly some other cancers.
  • Men with a BRCA gene change are at increased risk of breast cancer , prostate cancer, pancreatic cancer, and possibly some other cancers.

If you have a family history of breast cancer, you have a higher risk of getting breast cancer yourself. Most women with a family history of breast cancer do not have an inherited gene change that greatly affects their risk. Still, an inherited gene change is more likely in women with a strong family history of breast cancer, especially if the family history also includes certain other cancers, such as ovarian, pancreatic, or prostate cancer. The risk of having an inherited syndrome is also affected by:

  • Which family members are affected
  • The number of family members affected
  • The age when your relatives were diagnosed

Genetic Risk Factors For Breast Cancer: Clinical Applications

As understanding of the genetic basis of breast cancer increases, further refinement in genetic risk models can be expected. The different genetic basis of tumor subtypes is a clear example of where refinement might take place as genetic profiles become predictive of tumor characteristics. At this stage, it is already well established that women with, or at higher risk for, ER+ cancer are a good candidates for treatment with tamoxifen or raloxifene that specifically targets ER+ disease.

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How Does Genetic Testing For Breast Cancer Work

Genetic testing for breast cancer risk typically uses a sample of blood, saliva, or cells from the inside of your cheek. After the sample is collected, its sent to a lab specializing in genetic testing to be analyzed.

Several gene variations that increase breast cancer risk have been found. The most important are those in the BRCA1 and BRCA2 genes. According to the National Cancer Institute, about people have a harmful BRCA variation.

About of females with harmful BRCA1 and 45 to 69 percent of females with harmful BRCA2 variations will develop breast cancer by age 80. Their risk of getting breast cancer in the other breast is also higher.

Other gene variants that may raise breast cancer risk include:

  • PALB2

. A healthcare professional or genetic counselor will contact you and discuss your results.

Results you can receive include:

  • Positive: A known gene variation that increases your risk of breast cancer was detected.
  • Negative: A known gene variation that raises your risk of breast cancer was not detected.
  • Variant of unknown significance: A variant has been found in a gene, such as BRCA1 or BRCA2, but its impact on breast cancer risk is currently unknown.

Genetic testing results can be complex. Work with a genetic counselor to help understand what your results mean, so you can plan for next steps.

What Do Brca1 And Brca2 Genetic Test Results Mean

Is Genetic breast cancer testing of all women worth the cost?

BRCA1 and BRCA2 mutation testing can give several possible results: a positive result, a negative result, or a variant of uncertain significance result.

Positive result. A positive test result indicates that a person has inherited a known harmful variant in BRCA1 or BRCA2 and has an increased risk of developing certain cancers. However, a positive test result cannot tell whether or when the tested individual will develop cancer. Some people who inherit a harmful BRCA1 or BRCA2 variant never develop cancer.

A positive test result may also have important implications for family members, including future generations.

  • Both men and women who inherit a harmful BRCA1 or BRCA2 variant, whether or not they develop cancer themselves, may pass the variant to their children. Each child has a 50% chance of inheriting a parents variant.
  • All blood relatives of a person who has inherited a harmful BRCA1 or BRCA2 variant are at some increased risk of having the variant themselves. For example, each of that persons full siblings has a 50% chance of having inherited the variant as well.
  • Very rarely, an individual may test positive for a harmful variant not inherited from either parent. This is called a de novo variant. Such a variant is one that arose in a germ cell of one of the parents and is present in all the cells of the person who grew from that cell. The children of someone with a de novo variant are at risk of inheriting the variant.

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