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Understanding Carrier Status in Hereditary Cancer Testing
Many patients are surprised to learn that hereditary cancer genetic testing can sometimes identify carrier status results in addition to information about cancer risk. Seeing the word “carrier” on a hereditary cancer test report can feel confusing at first.
What Is a Carrier Result?
Carrier results are related to genes associated with recessive genetic conditions. Recessive conditions occur when a person has a pathogenic (harmful) genetic variant in both copies of a gene. A carrier result means a person has a pathogenic variant in only one copy of the gene.
Typically, carriers are healthy and do not have symptoms of the condition. However, if both biological parents are carriers for the same condition, there may be a chance for a child to inherit the condition.
Carrier status is most commonly discussed in the context of family planning and pregnancy. Some common non-cancer-related examples of recessive conditions include:
-Cystic fibrosis
-Beta thalassemia
-Spinal muscular atrophy (SMA)
Why Would a Hereditary Cancer Test Show Carrier Status?
Most hereditary cancer conditions are inherited in a dominant pattern, meaning a pathogenic variant in one copy of the gene can increase cancer risk. However, some genes included on hereditary cancer panels can also be associated with recessive conditions, which is why carrier results may occasionally appear on hereditary cancer testing.
There are two important ways this can happen.
- Some Genes Are Associated With Both Cancer Risk and Recessive Conditions
For certain genes, having a pathogenic variant in one copy of the gene is associated with an increased risk of cancer, while having pathogenic variants in both copies of the gene can cause a separate recessive condition that may involve additional health concerns beyond increased cancer risk.
In these situations:
-A person with one pathogenic variant may receive a positive hereditary cancer result because the finding affects their own cancer risk and medical management.
-A person with two pathogenic variants may have a distinct recessive condition that can involve cancer risk as well as other medical features.
Although these results may have implications for family planning, they are not considered “carrier-only” findings because they can directly impact the individual’s health.
- Some Recessive Cancer Conditions Have True Carrier States
Other hereditary cancer conditions are recessive, meaning cancer risk is only increased when a person has pathogenic variants in both copies of the gene.
For these conditions, individuals with a pathogenic variant in only one copy of the gene are considered carriers and typically do not have increased risks or symptoms related to that condition. Some of these conditions may only carry cancer risk while others may carry risk for other medial features in addition to cancer risk.
In these cases, the result is mainly important for reproductive and family planning purposes rather than changes to the individual’s cancer screening or medical care.
Does a Carrier Result Change Cancer Screening?
In most cases, carrier only results identified on hereditary cancer testing do not change cancer screening recommendations. However, they may still be important for:
-Future family planning
-Informing biological relatives
-Considering partner testing
-Understanding reproductive risks
Reviewing results with a genetics professional is important to fully understand whether a finding is associated with personal cancer risk, carrier status only, or both.
Why Genetic Counseling Can Help
Genetic test reports often contain unfamiliar medical language, and seeing unexpected results can feel overwhelming. Many people learn they are carriers unexpectedly through genetic testing, and this is common. A genetic counselor or genetics provider can help explain:
-Whether a result is related to cancer risk
-Whether the finding represents carrier status only
-Whether family members should consider testing
-If any follow-up is recommended
Not every genetic result changes medical care, but understanding the meaning of results can help patients make informed decisions for themselves and their families.
While hereditary cancer findings and carrier results do not always have the same healthcare implications, both can provide valuable information about personal health and family planning. If you have questions about your genetic testing results, speaking with a genetics professional can help clarify what the findings may mean for you and your family.
Cassidy Pedraza, MS, CGC
Cassidy joined Ironwood Cancer Center and Research Centers in February 2025. She obtained her Bachelor of Science in Biology with a minor in psychology from Cal Poly San Luis Obispo and her Master of Science in Genetic Counseling from Arizona State University. During her training at Arizona State, she completed several clinical rotations at various institutions including Banner, Mayo Clinic, Ironwood Cancer Center, and Phoenix Children’s Hospital. She is a member of the National Society of Genetic Counselors. Her interests in genetic counseling include cancer genetics and improving health care access. Outside of work, Cassidy enjoys traveling, spending time with her friends and family, and trying new restaurants.