BRCA Overview

BRCA1 vs. BRCA2

BRCA1  and  BRCA2  are just two of about 20,000 genes inside of every cell of your body. They are tumor suppressor genes, which means they play a role in controlling or preventing cancer. Both men and women have  BRCA1  and  BRCA2  genes. When there is a mutation in a  BRCA1  or  BRCA2  gene, an individual has increased cancer risks. They can also pass the mutation on to their children who will then have increased cancer risks in adulthood.

Are mutations in BRCA1 and BRCA2 the only ones that increase cancer risk?

While it is known that mutations in BRCA1 and  BRCA2 can increase cancer risk, it is also known that there are other genes that impact a person’s cancer risks. Genetic testing of genes other than BRCA1 and BRCA2 may be suggested if there is a significant chance of finding information that will impact medical care. It is likely there are more undiscovered genes that increase breast or ovarian cancer risk.

Better testing technologies are allowing researchers to take an in depth look at the entire DNA sequence. Through this “whole genome” approach more and more cancer susceptibility genes will be identified. It will take time to determine if these genes increase risk enough to impact medical care.

Are BRCA1 and BRCA2 mutations common? Are Ashkenazi Jewish people more likely to have them?

Inherited mutations in the genes  BRCA1  and  BRCA2  are rare. Only about 1 in 200 individuals have a mutation. However, these gene mutations are more common in certain ethnic groups. For example, men and women of Eastern or Central European Jewish descent (Ashkenazi Jewish) have a 1 in 40 chance of having a  BRCA1  or  BRCA2  mutation.

Can men and women carry a BRCA mutation?

Both men and women can inherit and pass on a BRCA gene mutation. Both men and women with a BRCA mutation have increased cancer risks.

What are the cancer risks for people with mutations in BRCA1 and BRCA2?

A positive BRCA1 or BRCA2 test result means that a person has an inherited mutation in either gene and is at increased risk for certain cancers. The cancer risks associated with BRCA1 and BRCA2 in men and women carrying mutations are presented as ranges.

Do all people with BRCA mutations develop cancer?

People with mutations in BRCA1 or BRCA2 may develop one or more cancers, or they may not develop cancer at all. Unfortunately, being diagnosed with one type of cancer does not mean that other cancer risks no longer apply. For example, women with a BRCA mutation with breast cancer are at increased risk of developing a second new breast cancer and other cancers.

What is PALB2 and what does it mean for me?

Like BRCA1 and BRCA2, PALB2 is one of the body’s roughly 20,000 genes. The PALB2  gene produces proteins that work with the BRCA2 gene. Mutations can occur in the PALB2 gene but are quite rare and are found in 1% of women with breast cancer.

Individuals with a PALB2 mutation have an increased risk of breast cancer. Current research has shown that PALB2 mutations increase a woman’s risk of breast cancer to 40-60% by age 70 and can be higher depending on her family history. PALB2 mutations also appear to increase the risk of male breast cancer and pancreatic cancer; although the exact lifetime risks are unknown. Research is ongoing to determine if PALB2 mutations increase the risk for other cancers.

If you have tested positive for a BRCA1 or BRCA2 mutation and are being followed under a personalized cancer risk management plan, it is highly unlikely that testing for PALB2 would be helpful to you because your hereditary risk is already known.

If you’ve tested negative for a BRCA1 or BRCA2 mutation, please speak to your genetic counselor about whether testing for additional genes that increase cancer risk makes sense for you in the context of your personal and family history.

Genetics is a constantly evolving field. Questions about testing for additional genes that may increase cancer risk should be directed to your genetic provider.

Genes are the instruction manuals within in all of our cells. Genes are made up of DNA, which act as letters that spell a chemical code. Through the chemical code the body receives messages that control every bodily function. Most body functions, such as digestion, are complicated and involve not just one, but many genes. Certain genes may produce brown hair while other genes send messages for blonde hair. 

When a gene is not working properly, it is said to be altered or mutated. A gene mutation may disrupt a normal body function. If certain genes, like BRCA1 and BRCA2, have errors or mutations, they stop working properly and the cells may not get the proper instructions about when to grow and divide. Cells can then grow more quickly without the normal genetic controls, and form a tumor.

What is cancer risk evaluation?

Cancer risk evaluation involves meeting with a genetics specialist to estimate your personal risk for different cancers by reviewing your personal and family history of cancer, and sometimes undergoing genetic testing. Knowing about the presence of increased risk for cancer can provide important, sometimes life-saving options such as increased cancer screening, prophylactic surgeries, and medications

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How can cancer risk run in a family?

Genes are inherited from your parents. We all have two copies of each gene – one copy is inherited from our mother and one copy from our father. Most mutations in cancer risk genes, like BRCA1 and BRCA2 , are called dominant mutations. This is because having a mutation in only one copy of the gene is enough to increase cancer risk.

A parent who has a mutation in a cancer risk gene has a 50% chance of passing it on to each of his/her children, and a 50% chance of passing on the normal copy of the gene. Men, as well as women, can inherit and pass on a mutation in a cancer risk gene to either a son or a daughter.

Who should consider genetic testing?

A complete personal and family history, including at least three generations of relatives on both you mother and father’s side of the family, should be examined to determine if a mutation is present in a high risk cancer gene. Consider genetic risk evaluation if you or a family member has had*:

• Breast cancer at age 65 or younger
• Triple negative breast cancer at any age
• Ovarian or fallopian tube cancer at any age
• More than one breast cancer diagnosis
• Male breast cancer
• Pancreatic cancer
• Metastatic prostate cancer
• Anyone of Ashkenazi Jewish ancestry
• A known mutation in a cancer risk gene
• Breast, ovarian, pancreatic, or high grade prostate cancer diagnosed in multiple individuals on the same side of the family

* A genetics specialist can help to determine if your personal and/or family history meets these or other criteria.

The human body is made of millions of individual cells. Cancer is a condition where certain cells in the body are no longer growing and dividing normally. Cancer cells may grow too quickly and form a lump, or a  tumor. 

When cancer cells are seen under a microscope, they show certain distinct features. A pathologist, a physician specializing in the study of cells, can determine if they are cancerous. If cancer is present, a tumor is malignant. If cancer is not present, a tumor is considered benign.

How can cancer risk run in a family? 

Genes are inherited from your parents. We all have two copies of each gene – one copy is inherited from our mother and one copy from our father. Most mutations in cancer risk genes, like BRCA1 and BRCA2, are called dominant mutations. This is because having a mutation in only one copy of the gene is enough to increase cancer risk.

A parent who has a mutation in a cancer risk gene has a 50% chance of passing it on to each of his/her children, and a 50% chance of passing on the normal copy of the gene. Men, as well as women, can inherit and pass on a mutation in a cancer risk gene to either a son or a daughter.

Managing Cancer Risk