Hereditary Cancer Testing | It’s In the Genes
One of the more exciting aspect of medicine that has the potential to impact health care and clinical decision making, is the evolution underway with genetic testing. Just over a decade ago there was simply one gene that we could test for, the BRACA gene, as many people have become familiar with.
Angelina Jolie is one prominent cultural personality who assisted in moving that specific screening exam into the cultural consciousness, when she chose in 2013 to undergo an elective double mastectomy after learning she tested positive for the BRACA1. She had been informed of an “87% risk for developing breast cancer and 50% risk of ovarian cancer”, and was well aware of what that could mean to her and her family, after having lost her own mother to ovarian cancer in 2007 at the age of 56 years old.
Her story brought publicity to the issue. BRCA stands for breast cancer susceptibility genes, a class of genes known as tumor suppressors. Discovered in the early 1990’s, BRCA1 and BRCA2 proteins are normally expressed in the cells of breast and other tissue, where they help repair damaged DNA, or destroy cells if DNA cannot be repaired. If BRCA1 or BRCA2 itself is damaged by a BRCA mutation, damaged DNA is not repaired properly, and this increases the risk for breast cancer. Both the BRCA1 and BRCA2 genes have been linked to hereditary breast and ovarian cancer.
Today, BRCA1 and the related BRCA2 are responsible for around 5% of breast cancer cases in the U.S., or up to 25% of inherited breast cancer. Screening (hereditary cancer testing) for changes in the genes can help steer women toward potentially lifesaving treatments.
Mary-Claire King, professor of genetics and medicine at the University of Washington, and the researcher credited with the discovery of the BRCA genes, stated in an interview with Time Magazine in 2014, “I am increasingly convinced that it is both feasible and a good idea to offer a blood test, a sequencing test for BRCA1 and BRCA2 and some of their sister genes for every woman after about age 30. Once a young woman reaches 30 or so, if she has a mutation in one of the genes, she should know about it.”
But the potential value of genetic testing (hereditary cancer testing) does not end with the discovery of the BRACA genes. Upwards of 10% of cancers can be inherited. The Human Genome Project was a 13-year-long, publicly funded project initiated in 1990 with the objective of determining the DNA sequence of the entire human genome. Since its completion in 2003 additional genes have been identified that have a relationship to risk for familial or inherited cancers. Vantari Genetics, a California genetic testing company, has developed a screening panel that detects 144 genetic mutations that correspond to 91 types of cancer. With their screening comes valuable and much needed genetic counseling to assist a patient in assimilating the results.
In regards to some of the legal ramifications of this evolving technology, in March 2000, President Clinton announced that the genome sequence could not be patented, and should be made freely available to all researchers. Additionally the Supreme Court has ruled that BRCA1 and BRCA2 are not patentable, since they are products of nature, a decision that King supports so that more companies can now devise tests for the cancer-causing mutation.
There are obvious privacy concerns that might arise in a patient’s mind as it relates to genetic testing. However there are evolving safeguards to protect the healthcare consumer. In 1996 the United States passed the Health Insurance Portability and Accountability Act (HIPAA) which protects against the unauthorized and non-consensual release of individually identifiable health information to any entity not actively engaged in the provision of healthcare services to a patient
Additionally, the Genetic Information Nondiscrimination Act of 2008 (enacted May 21, 2008, GINA, pronounced Gee-na), is an Act of Congress in the United States designed to prohibit the use of genetic information in health insurance and employment. The Act prohibits group health plans and health insurers from denying coverage to a healthy individual or charging that person higher premiums based solely on a genetic predisposition to developing a disease in the future. The legislation also bars employers from using individuals’ genetic information when making hiring, firing, job placement, or promotion decisions. While GINA has been cited as a strong step forward, some say that the legislation does not go far enough in enabling personal control over genetic testing results. The law does not cover life, disability, or long-term care insurance, which may cause some reluctance to get tested.
One of the tasks of a primary care clinician is to assess family history and thus determine areas of elevated or higher risk, medically speaking. For some this may be a propensity for high blood pressure, cholesterol, or diabetes. However for some people they are all too aware of a high familial incidence for certain cancers. Although genetic testing does not always give you clear answers, genetic counselors are trained to interpret and explain the test results and what they might mean to you and your family. If a mutation is found, the counselor will talk to you about which of your family members might also be affected. It will be important for those family members to know exactly which mutation was found and in which gene. They can then discuss this information with their doctors and consider being tested, too.
When looking at your personal and familial health histories (hereditary cancer testing) the cancers that are most alarming for potentially being hereditary and thus suggesting higher risk are:
- Several first-degree relatives (mother, father, sisters, brothers, children) with cancer, especially if they’ve had the same type of cancer
- Cancers in your family that are sometimes linked to a single gene mutation (for instance, breast, ovarian, and pancreatic cancer).
- Family members who had cancer at a younger age than normal for that type of cancer
- Close relatives with rare cancers that are linked to inherited cancer syndromes
- A physical finding that is linked to an inherited cancer (such as having many colon polyps)
- A known genetic mutation in one or more family members who have already had genetic testing
We’ve all heard the phrase that knowledge is power, and with the potential acquisition of our genetic blueprint, or data that relates to risk for disease, we can be empowered to know where to focus our attention and energy, whether it relate to a change in screening recommendations, or at times a decision for a preventive surgery such as what Angelia Jolie chose. A negative result on a genetic test in families at risk for a specific cancer may help relieve anxiety or uncertainty. A positive result can assist you to make critical decisions about your future, perhaps including things you can do to help lower your risk. A positive result may also lead to finding disease earlier, when treatment is more likely to be helpful.
Here at Austin Family Medicine Associates we offer hereditary cancer testing that focus on up to 144 genes across 91 hereditary cancer syndromes. After a thorough review of your family pedigree with your clinician, a collection of a DNA is accomplished through a simple, quick and painless salivary sample that is then sent forward to the laboratory for genetic testing. Results are then available in 2-3 weeks, and a plan is then constructed through a review of the detailed report. Genetic counseling services are included with the testing at no additional charge, and a plan is then constructed to review your options. If you or a loved one has concerns about the risk of cancer in your family, we urge you to come in and speak with one of our providers here at Austin Family Medicine Associates to see if Hereditary Cancer Testing is right for you.
Additional resources for information include:
American Cancer Society
Toll-free number: 1-800-ACS-2345
National Cancer Institute
Toll-free number: 1-800-4-CANCER (1-800-422-6237)
National Society of Genetic Counselors (NSGC)