Genes tell us a lot about a person — hair color, eye color, blood type. Now, genetic specialists are using our DNA’s building blocks to answer questions about cancer risk. This process, called genetic testing, can help identify which cancers a person is more likely to develop based on their heredity, changing how we think about personalizing healthcare and cancer prevention.
Genes Speak a Unique Language. What Are They Saying about Cancer?
There are a variety of factors that can cause cancer, including environmental exposures, lifestyle choices, and aging. But only around 10% of cancers are tied to an inherited genetic mutation passed down from a biological parent. These inherited mutations can be identified through genetic testing.
“[Genetic testing] may be able to determine if a person has an increased risk of developing certain cancers and may explain why a person developed cancer,” says Alex Wadley, a genetic counselor at UAMS. The results can also help guide decisions about future screenings.
Inherited and Non-Inherited Cancers
Not all cancers are inherited. But all cancers cause changes in our DNA.
“[Cancer] impacts our cells’ ability to control cell growth or repair DNA,” Alex says. “Most of the time, these changes are acquired throughout our lifetime and are considered ‘sporadic.’”
Red flags that may point to a hereditary cancer condition include:
- Being diagnosed with cancer under age 50
- Having multiple cancer diagnoses
- Developing a rare tumor or type of cancer
- A family history of multiple relatives across generations with cancer
Genetic Testing for Cancer Risk
A doctor may refer a patient with one of these red flags to a genetic specialist who will perform genetic testing to get a clearer picture of their cancer risk. Genetic testing involves sending a blood or saliva sample to a clinical laboratory that looks for specific mutations. Depending on a patient’s personal or family history, a multi-gene panel might be recommended to check for a group of genes linked to one or more cancer types.
Because it is specific to the patient’s personal and family history, not every person needs genetic testing. “Meeting with a genetics professional, such as a certified genetic counselor, can be helpful,” Alex says. “They can walk through a patient’s health and family history, explain how testing works, and offer support throughout the testing process.”
When results come back, they usually fall into one of three categories:
- Positive (diagnostic)
- Negative (no reportable mutations found)
- Variant of uncertain significance (also called a VUS)
A positive result indicates that a genetic mutation was found that may explain why a person developed cancer — or if they haven’t had cancer, it may mean they’re at increased risk. In either case, the gene might be passed on in the family, and a genetic specialist would likely recommend more frequent cancer screenings.
A negative result means that no genetic mutations were found that would explain why a person developed cancer or has a family history of cancer. “A negative result does not eliminate the possibility of a hereditary cancer mutation within the family,” Alex adds. “But, it gives us reassurance based on current technology.” The genetic specialist may still recommend more frequent screenings.
A VUS result means a gene change was found, but the lab cannot confirm whether it’s harmful or harmless. “We all have differences in our genetic code. That’s why we look and act different,” Alex explains. “If a patient receives a VUS, the important thing is not to panic.” A genetic counselor can help review your report, dig into what’s known about that variant, and be the point of contact if the results are reclassified in the future.
Clarifying Positive Results
It’s important to remember: a positive result does not mean a patient has cancer. Rather, it would confirm why a patient developed cancer or tell us which cancers a person is at risk of developing. More frequent screenings can help spot any early signs of cancer.
Some patients may have concerns about false positives or false negatives, but these are rare. “Genetic testing is sequencing a person’s DNA, so if a pathogenic mutation is identified, we would trust the results,” Alex says.
Genetic testing will never diagnose a cancer, but it can help in risk assessment. Patients should still get regular cancer screenings, such as mammograms and colonoscopies. Screenings can help determine if more in-depth follow-ups are needed. Some screening tools, for instance, can determine if a woman’s lifetime risk of developing breast cancer is above the general population risk and if additional breast imaging may be needed.
Overcoming Privacy and Discrimination Concerns
Some patients understandably express concerns about privacy and discrimination, especially regarding genetic test results. HIPAA laws protect all health information, including genetic testing results. And the Genetic Information Nondiscrimination Act (GINA) protects patients from discrimination based on genetic information and test results. That said, there are exceptions to any law, especially regarding life insurance, long-term care coverage, and disability insurance, so it’s good to talk through any concerns.
Resources and Final Thoughts
If patients are still unsure about genetic testing, the National Society of Genetic Counselors has a wealth of information about what to expect from a genetic counseling appointment, and the CDC provides a good general overview of the process.
“Genetics is a quickly evolving field with new genes being discovered and testing technology rapidly expanding,” Alex says. “Due to this rapid expansion, genetic testing criteria are regularly updated. If a patient’s personal or family history makes you think there might be a hereditary link, refer them to cancer genetics for a formal evaluation.”
There are four main cancer clinics in Arkansas that perform genetic testing:
- UAMS (501-526-4812)
- CARTI (1-800-482-8561)
- Baptist Health (501-202-7295)
- Highlands Oncology (479-313-6826)
Meet Alexandrea Wadley
Alexandrea (Alex) Wadley, MMSc, LCGC, is a licensed certified genetic counselor. She practices at the UAMS Winthrop P Rockefeller Cancer Institute and holds a faculty appointment in the UAMS College of Health Professions, where she is core faculty and Interim Assistant Program Director for the Genetic Counseling Graduate Training Program. Alex has a passion for providing genetics education, whether that be to patients, the community at large, or to trainees. Alex is an advisor for multiple genetic counseling student research projects and serves as course director for the psychosocial genetic counseling courses. She is a clinical supervisor and lead genetic counselor for the cancer genetics clinic, where she has worked to expand cancer genetic counseling services at UAMS. Alex has a Bachelor of Arts in Biochemistry and Molecular Biology from Hendrix College and a Master of Medical Science in Human Genetics and Genetic Counselor from Emory University School of Medicine. She is a diplomate of the American Board of Genetic Counseling and holds an active genetic counseling license from the Arkansas State Medical Board.
