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Genetics and Breast Cancer

Hereditary Breast Cancer

Up to 10% of breast cancers may be hereditary, meaning they are caused by a genetic mutation inherited from a parent. Three of the most well-known genes that can mutate and raise the risk of breast cancer are BRCA1, BRCA2, and PALB2. People who inherit a mutation in any of these genes from their mothers or fathers have a higher-than-average lifetime risk of developing breast cancer, ovarian cancer, or certain other cancers. Normally, the BRCA and PALB2 genes keep breast cells growing normally and prevent cancer cell growth. But when these genes contain mutations that are passed from generation to generation, they stop functioning normally and increase the risk of breast and other cancers.

Sources: 

[Note: BRCA, which is short for BReast CAncer, is usually pronounced by saying the names of the four letters: B-R-C-A.]

Inherited mutations in the following genes also increase the risk of breast cancer:

  • ATM
  • BARD1
  • CDH1
  • CHEK2
  • NF1
  • PALB2
  • PTEN
  • RAD51C
  • RAD51D
  • STK11
  • TP53

For more information about these genes, see  “Inherited Gene Mutations” on the Susan G. Komen website

BRCA Genes and Breast Cancer

“About 1 in 500 women in the U.S. will have a BRCA1 or BRCA2 mutation,” says genetic counselor Joyce Turner.

“BRCA just stands for breast cancer. Without treatment, a woman who is BRCA1 or BRCA2 mutation carrier is seven times more likely to develop breast cancer and 30 more times likely to develop ovarian cancer before the age of 70.

A 3-minute video from the CDC.

Understanding BRCA Mutations and Risk

Everyone has the BRCA genes. Their job is to repair errors that occur in your cell’s DNA. If one or both genes you inherited have a mutation, they might let some errors through.

Men can also carry the mutated gene and those men are at an increased risk of developing breast, prostate and pancreatic cancer.

A 4-minute video from the Dr. Susan Love Foundation

Dispelling myths of BRCA gene mutations

BRCA mutations have been linked to breast, ovarian, pancreatic and prostate cancers, all of which aside from ovarian cancer, can affect men.

Men are just as likely as women to possess a BRCA mutation which raises their risk for certain cancers.

A 4-minute video from AstraZeneca.

 

My Experience as a BRCA Mutation Carrier

Erika Stallings is a lawyer, writer, and patient advocate based in New York City. In 2014, she learned that she carried a BRCA2 mutation, like her mother, and underwent a preventative mastectomy later that year.

“Despite my risk, I avoided getting tested right away. I was busy living life. Before I knew it, I was 28 years old, about the same age that my mom was first diagnosed.

I knew I needed to get tested. Looking back, I’m a little embarrassed that I pushed it off. But when you’re young, you feel healthy. You don’t expect these huge hurdles to come up, even if you know you’re at risk.

I tried to make an appointment for genetic testing at Memorial Sloan Kettering, but was waitlisted due to a shortage of genetic counselors in the United States.

In June 2014, I got an appointment at New York University. I did some volunteer work for a breast cancer organization in New York City, and the executive director helped me get an appointment. If it weren’t for them, I would’ve had to wait another six months.

In July, I got the results. I had inherited the BRCA2 mutation. I knew it.”

Source: “My Experience As a BRCA Mutation Carrier”(August 25, 2021)

Black & BRCA is a collaboration between the Basser Center for BRCA and its team of patient advocates, researchers and healthcare professionals to bring tailored resources and support to the Black community. The Basser Center is part of the University of Pennsylvania Health System, a major multi-hospital health system headquartered in Philadelphia, Pennsylvania.

“At a time when Black men and women are more likely than the general population to be diagnosed with cancer at later stages when it is less treatable, Black & BRCA seeks to empower individuals to understand their family health history and take action to prevent cancer from one generation to the next.”

Educational Resources

BRCA1 and BRCA2 in Men

Men can also carry BRCA1 or BRCA2 gene mutations and be at increased risk for breast, prostate and other cancers, too.

While cancer risks in male BRCA mutation carriers are not as dramatically elevated as those of female BRCA mutation carriers, cancer risk management and early detection are crucial.

See “BRCA1 and BRCA2 in Men” on the Basser Center for BRCA website

Beyonce's father is a BRCA carrier

Everyone has BRCA1 and BRCA2 genes and men can carry BRCA1 or BRCA2 gene mutations and be at increased risk for breast, prostate and other cancers, too.

While cancer risks in male BRCA mutation carriers are not as dramatically elevated as those of female BRCA mutation carriers, cancer risk management and early detection are crucial.

See “BRCA1 and BRCA2 in Men” on the Basser Center for BRCA website

Disparities in pathogenic variants

News about disparities in variants

Disparities in genetic testing

Testing for the BRCA genes isn’t routinely performed in people with an average risk of breast cancer. It’s usually offered only to those who are likely, based on a personal or family history of cancer, to have an inherited mutation. The identification of a mutation may affect the treatment recommendations, make a patient eligible for certain clinical trials, and alert other members of a family that they may have also inherited the mutated gene.

Genetic testing performed prior to 2014 most likely would not have had PALB2 or other potentially relevant genes included and may not have included testing for large genomic rearrangements in BRCA1 or BRCA2, so updated testing should be considered.

News about disparities in genetic testing

Genetic mutations and testing

African American and White Women share the same genes that increase the risk of breast cancer

The same genes that increase the risk of breast cancer in U.S. White women also greatly increase breast cancer risk among African American women.

These genes include the BRCA1, BRCA2 and PALB2 genes, each of which is associated with a more than seven-fold risk of breast cancer, as well as four other genes associated with a more moderate increase in risk.  Previous studies of women of African ancestry were too small to assess genes other than BRCA1 and BRCA2.

“This means that the multi-gene panels that are currently available to test women diagnosed with breast cancer or women at high risk due to their family history will be useful for African American women,” explains Julie Palmer, ScD, (left) of the Boston University School of Medicine.

Researchers in 2020 sequenced the germline (inherited) DNA from 5,054 African American women with breast cancer and 4,993 age-matched African American women without cancer for mutations in 23 genes linked to a predisposition for cancer. They then estimated the risks of developing breast cancer associated with having a mutation in any of the genes.

Rates of genetic mutations are similar between Black and White women diagnosed with breast cancer

In a 2021 study of 3,946 Black women diagnosed with breast cancer and 25,287 White women also diagnosed with the disease, the rates of genetic mutations in genes linked to breast cancer were similar. Among the Black women, 5.65% had a mutation in one of the 12 genes, compared with 5.06% of the White women, a difference that is not statistically different.

The researchers, led by Susan Domchek, MD, (right) of the University of Pennsylvania, concluded that all efforts should be made to ensure equal access to genetic testing to minimize disparities in care and outcomes in women diagnosed with breast cancer.

The study also confirmed that Black women were more likely to be diagnosed with breast cancer at a younger age, more likely to be diagnosed with triple-negative breast cancer, and more likely to be diagnosed with estrogen-receptor-negative breast cancer (which tends to grow faster than hormone receptor-positive cancer).

BRCA1 and BRCA2 genes

About 5% to 10% of breast cancer cases are thought to be hereditary, meaning that they result directly from gene changes (mutations) passed on from a parent.  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. It goes up if more family members are affected.

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.  Men who inherit one of these gene changes also have a higher risk of breast, prostate and some other cancers.

In the United States, BRCA mutations are more common in Jewish people of Ashkenazi (Eastern Europe) origin than in other racial and ethnic groups, but anyone can have them.

See: “Breast Cancer Risk Factors You Cannot Change” on the American Cancer Society website

BRCA Genes and Breast Cancer

Without treatment, a woman who is BRCA1 or BRCA2 mutation carrier is seven times more likely to develop breast cancer and 30 more times likely to develop ovarian cancer before the age of 70.

A 3-minute video from the CDC.

Understanding BRCA Mutations and Risk

Everyone has the BRCA genes. Their job is to repair errors that occur in your cell’s DNA. If one or both genes you inherited have a mutation, they might let some errors through.

A 4-minute video from the Dr. Susan Love Foundation.

Dispelling myths of BRCA gene mutations

BRCA mutations have been linked to breast, ovarian, pancreatic and prostate cancers, all of which aside from ovarian cancer, can affect men.

A 4-minute video from AstraZeneca.

Black & BRCA is a collaboration between the Basser Center for BRCA and its team of patient advocates, researchers and healthcare professionals to bring tailored resources and support to the Black community. The Basser Center is part of the University of Pennsylvania Health System, a major multi-hospital health system headquartered in Philadelphia, Pennsylvania.

“At a time when Black men and women are more likely than the general population to be diagnosed with cancer at later stages when it is less treatable, Black & BRCA seeks to empower individuals to understand their family health history and take action to prevent cancer from one generation to the next.”

Educational Resources

My Experience as a BRCA Mutation Carrier

Erika Stallings is a lawyer, writer, and patient advocate based in New York City. In 2014, she learned that she carried a BRCA2 mutation like her mother. 

Despite my risk, I avoided getting tested right away. I was busy living life. Before I knew it, I was 28 years old, about the same age that my mom was first diagnosed.

I knew I needed to get tested. Looking back, I’m a little embarrassed that I pushed it off. But when you’re young, you feel healthy. You don’t expect these huge hurdles to come up, even if you know you’re at risk.

I tried to make an appointment for genetic testing at Memorial Sloan Kettering, but was waitlisted due to a shortage of genetic counselors in the United States. In June 2014, I got an appointment at New York University. I did some volunteer work for a breast cancer organization in New York City, and the executive director helped me get an appointment. If it weren’t for them, I would’ve had to wait another six months.

In July, I got the results. I had inherited the BRCA2 mutation. I knew it.” She underwent a preventative mastectomy later that year.

Source: “My Experience As a BRCA Mutation Carrier”(August 25, 2021)

Recent news about disparities in genetic mutations

News about disparities in genetic testing

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