Jill Stopher, MS, CGC
The Abramson Cancer Center of the University of Pennsylvania
Ultima Vez Modificado: 21 de marzo del 2013
BRCA1 and BRCA2 is short for breast cancer susceptibility gene 1 and breast cancer susceptibility gene 2. The BRCA1 and BRCA2 genes are present in all individuals. Everyone has two copies of each of these genes - one from each parent.
Mutations of genes are like spelling errors in the genetic code of a gene. Those who have a gene mutation in either the BRCA1 or BRCA 2 gene are at higher than average risk for developing certain cancers.
The BRCA1 and BRCA2 genes are responsible for the repair of certain types of DNA errors that may occur each time a human cell makes a copy of itself. Without a gene mutation, functional BRCA1 and BRCA2 genes help ensure the stability of a cell's genetic material, or DNA, and help prevent uncontrolled cell growth. Mutations of these genes have been linked to an increased genetic risk for multiple forms of cancer, but most notably breast and ovarian cancer.
Having mutations of genes, or an inherited mutation in BRCA1 or BRCA2 does not mean a person is guaranteed to develop cancer, but the chances are significantly higher than for someone who does not have a gene mutation.
Women who inherit a harmful mutation in BRCA1 or BRCA2 have a lifetime risk of developing breast cancer of 50-80%, compared to 13% for an average woman without the mutation. Their lifetime risk of developing ovarian cancer is 10-45%, compared to 1-2% for an average woman without the mutation. These women have an increased risk of developing breast and/or ovarian cancer at an earlier than average age and may have multiple, close family members who have been diagnosed with these conditions.
Mutations in BRCA1 or BRCA2 may also increase the risk for pancreatic cancer and melanoma in both women and men. Men also have a higher chance to develop an earlier onset prostate cancer or male breast cancer if a BRCA2 gene mutation is present.
In a family with a history of breast and/or ovarian cancer, the first step may be to test a family member who has had breast or ovarian cancer. If that person is found to have a harmful BRCA1 or BRCA2 mutation, then other family members can be tested to see if they also have the mutation.
If there is no family member who has had the disease available for testing, a person can still be tested for the most common BRCA1 & 2 mutations. The first step is to meet with a genetic counselor who will help you explore what having genetic testing can mean for you, the risks and benefits to testing and how results will affect cancer screening and prevention recommendations for you.
Guidelines recommend that a woman be screened if any of the following apply:
People who learn about inherited risk for cancer can take steps to substantially increase the odds of good health. These include:
This varies from one policy to another. The genetic counselor will determine how likely it is that you could have a mutation. Most insurance companies will cover the cost of testing for those with a significant chance of having a mutation.
Learning you have a significantly higher chance to develop cancer one day can be scary for anyone - so it is important to consider the value in learning this information for children, teenagers and young adults.
Extensive research in families with known genetic risk due to BRCA1 and BRCA2 has shown that there is no increased risk for cancer in children. Therefore, there are no recommended interventions or special screening methods implemented during childhood. In addition, by choosing to test a child, a parent takes away that individual's right to decide whether, and when to receive this information. Legally someone can pursue genetic testing for BRCA1/2 mutations at age 18, but it is important to know that even at age 18, screening and follow-up recommendations will not change. This is because the cancer risks associated with BRCA1/2 rarely manifest before the late 20's or 30's. So at age 18, national guidelines show there is still isn't much to do even if a BRCA1 or BRCA2 mutation is present.
At age 25 however, things start to change for young women. Women who test positive for a BRCA1 or BRCA2 gene mutation generally start annual mammography, breast MRIs and breast exams at age 25. Therefore, some find this is an optimal time to consider testing. Young men are sometimes interested in pursuing genetic testing at later ages, since there is no screening that starts for men until later. However, some young men are interested in genetic testing to use in reproductive decision-making.
There is no "one size fits all" prescription for genetic testing. Genetic counseling allows each person to understand how they would be affected, and weigh the pros and cons of being testing based on their individual circumstances. Getting tested for a BRCA1 or BRCA2 gene mutation can be overwhelming at any age.
The good news is that there are now proven interventions to both lower cancer risk and optimize chances for early cancer diagnosis for those who are aware they carry this risk. Through the process of genetic testing, usually performed as a blood test, these genes can be examined. And, if a mutation in either BRCA1 or BRCA2 is discovered, women and men can take a proactive approach to preventive care and screening. Those who may already have cancer may receive personalized treatments based on those test results.
The Genetic Information Non-Discrimination Act (GINA) was signed into law in 2008. This federal law makes it illegal to raise a person's rates, drop coverage, or deny access to health insurance based on genetic information.
For people who have tested positive for a BRCA1 or BRCA2 gene mutation, the first and foremost thing to do is give yourself time to come to terms with what these test results mean to you. When you feel you are able, it may be important to consider a strategy for sharing this personal information with relatives in order to provide them with potentially lifesaving information. Often relevant people in the family to tell include:
Discussing the presence of genetic risk for cancer with the family can sometimes raise challenging issues. Some people don't want to upset their relatives, feel it's not the right time to tell a relative or just don't know how to bring it up.
Find out how much your relative knows about the BRCA1 or BRCA2 gene mutations. Be ready to share some general information about how BRCA1 or BRCA2 can affect someone's risk for developing certain kinds of cancer.
Start by sharing that you have been found to carry this genetic risk and that there are things family members can do to lower their own risk of cancer and improve their odds of early diagnosis.
You may suggest family members and friends get information for themselves from a qualified expert in cancer genetics. It's important to tailor your communication to the individual. You know best how a relative may react to this news.
Knowing about genetic risk for cancer informs someone about things they can do to improve their chances for good health. Knowing your genetic risk for cancer and family history can help you make informed decisions about screening, prevention and sometimes tailored treatments or therapies.
Sharing information about risk can be lifesaving. When you tell a family member about your increased genetic risk, you are empowering them to learn more about their own health and make their own informed decisions about health care.Imprima English