By Austin Coker
Genetic testing has changed the way many families understand cancer risk. A single test can sometimes explain why several relatives developed similar cancers, clarify who in a family is truly at elevated risk, and guide earlier or more personalized screening.
At the same time, genetic results are often misunderstood. A “negative” result does not always mean “no risk,” and a “positive” result does not mean cancer is inevitable.
For people who want a structured way to learn about hereditary risk and next steps, programs like CancerEDGE focus on education, clinically valid testing, and guidance, with an emphasis on the idea that early detection can change outcomes.
This article breaks down what cancer-related genetic testing can tell you, what it cannot tell you, and how to use results in a practical, medically responsible way.
Genetic information is powerful, but it works best when combined with your personal history, family history, and guidance from qualified clinicians such as licensed genetic counselors.
When most people talk about genetic testing and cancer, they are referring to germline genetic testing. Germline testing looks for inherited DNA changes that you were born with and that are present in nearly every cell of the body. These inherited variants can be passed down from parents to children.
This is different from tumor (somatic) testing, which analyzes DNA changes that occur in cancer cells over time. Tumor testing can help guide cancer treatment choices, but it does not always tell you whether a variant was inherited.
A third category that confuses is ancestry or recreational DNA testing, which may provide limited health reports but is not designed to be comprehensive or interpreted like clinical testing. In contrast, clinical hereditary cancer testing is typically performed in regulated laboratories, and results are ideally reviewed with a genetic counselor so you understand what is actionable and what is not.
The clearest value of clinical testing is identifying pathogenic or likely pathogenic variants in genes known to increase cancer risk. Some of the most recognized examples include:
BRCA1 and BRCA2, associated with a higher risk of breast and ovarian cancer, and also increased risk of prostate, pancreatic cancer, and melanoma in some individuals
Lynch syndrome genes (often including MLH1, MSH2, MSH6, PMS2, EPCAM), associated with increased risk of colorectal, endometrial, ovarian, stomach, and other cancers
APC, associated with familial adenomatous polyposis, a condition that can lead to hundreds to thousands of colon polyps
TP53, associated with Li-Fraumeni syndrome and elevated risk of multiple cancers at younger ages
PALB2, CHEK2, ATM, and others that can raise breast cancer risk, and sometimes additional cancer risks
If a clinically meaningful inherited variant is found, it can help explain family patterns and support more tailored prevention strategies.
For people with certain inherited variants, professional guidelines often recommend earlier, more frequent, or specialized screening. Examples can include:
Earlier breast screening with MRI for some high-risk gene carriers
Earlier colonoscopy or shorter intervals for Lynch syndrome
Additional screening tailored to gene-specific and family-history-specific risks
Your result does not automatically dictate a single plan. Screening decisions still consider your age, personal medical history, and family history. Genetic testing provides a high-quality input into that plan, especially when interpreted with help from licensed genetic counselors.
Some individuals with higher-risk variants may choose to discuss preventive options with their healthcare team. Depending on the gene and personal situation, that could include medications, surgical risk reduction, or targeted surveillance strategies.
A key point: genetic testing does not tell you what you must do. It helps you and your clinicians have a better-informed conversation about options.
When a clinically significant inherited variant is identified, it can guide cascade testing, meaning targeted testing for relatives. This is one of the most meaningful benefits of hereditary cancer testing.
If you carry a pathogenic variant, close relatives may have a higher chance of carrying it too. If they test negative for the known family variant, their risk often drops back closer to general population levels, though family history can still matter.
Some people pursue hereditary testing after a cancer diagnosis. Results can influence:
Risk of a second primary cancer
Screening for other cancers associated with the gene
Family risk assessment and testing for relatives
In some cases, treatment planning, especially when germline and tumor findings overlap
Genetic testing is not only for people who are healthy. It can still provide valuable insight after a diagnosis, particularly when paired with clinical navigation support such as a nurse navigator who helps patients understand information and coordinate resources.
Genetic testing is informative, but it is not a crystal ball. These limitations are not flaws. They are realities of biology and of what medical science can reliably interpret today.
Even with a high-risk variant, many people never develop cancer. Risk can be elevated, sometimes significantly, but it is rarely 100 percent. Penetrance varies by gene, by variant, by sex, and by family.
A positive result means:
Risk is higher than average for certain cancers
Prevention and screening discussions should be more personalized
It does not mean:
Cancer is inevitable
You have cancer now
A specific age of diagnosis can be predicted
A negative test result may be reassuring, but what it means depends on the situation:
True negative: A known pathogenic variant exists in the family, and you test negative for that exact variant. This often lowers your inherited risk substantially.
Uninformative negative: No known family variant exists, or the family history suggests hereditary risk, but testing did not find a cause. You can still have an increased risk due to factors not captured by the test.
Testing limitations: Not all genetic contributors are known, and some types of variants may be harder to detect depending on the method used.
This is why genetic results should be interpreted alongside a detailed family history. A negative result does not erase the impact of multiple relatives diagnosed young or with related cancers.
Most cancers are not caused by highly penetrant inherited variants. Cancer risk is influenced by many factors, including:
Age
Smoking and alcohol use
Obesity and metabolic health
Chronic infections (for example, HPV, hepatitis viruses)
Environmental exposures
Reproductive history and hormone exposure
Random DNA changes that accumulate over time
Genetic testing focuses on inherited risk. It does not measure these other contributors, though clinicians consider them in prevention planning.
Many people receive a result called a Variant of Uncertain Significance (VUS). A VUS means a change was found in a gene, but current evidence is insufficient to label it as harmful or benign.
What a VUS means in practice:
It should generally not drive major medical decisions on its own
Your medical plan should usually be based on your personal and family history, not the VUS
The classification can change over time as science improves, so follow-up matters
A careful counseling conversation is essential here. If you are unsure what a VUS means for your family, starting with a review session with a genetic counselor can help reduce confusion and prevent unnecessary steps.
Some companies offer polygenic risk scores that estimate risk based on many small-effect DNA markers. This area is evolving and may become more clinically useful over time, but it has important limitations today:
Performance can vary across ancestry groups due to how the datasets were built
Scores usually provide relative risk estimates, not certainty
Scores do not replace guideline-driven screening or a clinician’s evaluation
A practical way to understand cancer risk is to separate:
Hereditary risk: caused by identifiable inherited variants in specific genes
Familial risk: cancer clusters in a family for reasons that may include shared environment, shared lifestyle, chance, or genetic factors not yet identified
Sporadic risk: occurs without a strong family pattern and without a known inherited variant
Genetic testing is strongest at identifying hereditary risk. It is less able to explain familial risk when no clear pathogenic variant is found. That does not mean the family history is irrelevant. It means the explanation may be more complex than a single gene result.
Many people pursue testing because they simply want clarity. Clinically, genetic testing is often considered when there is:
Cancer diagnosed at a younger age than expected
Multiple relatives with the same or related cancers
Multiple primary cancers in one individual
Rare cancers or patterns suggestive of a hereditary syndrome
A known pathogenic variant in the family
Certain ancestry patterns are associated with a higher prevalence of specific variants
People without a strong family history sometimes test as well, especially since small families, limited knowledge of relatives’ health histories, adoption, and early deaths can hide hereditary patterns.
Clinical hereditary cancer testing usually follows a sequence:
Pre-test education and consent
You learn what the test can find, what it cannot, and what results may mean for you and your family.
Sample collection
Often saliva or blood. Many people use an at-home DNA test kit that is shipped after consent and returned using a prepaid mailer.
Laboratory analysis
Many tests use multi-gene panels that look at multiple genes associated with hereditary cancer.
Results interpretation
This is where genetic counseling becomes critical. A result is only as useful as its interpretation in your real-life context, which is why review with a licensed genetic counselor is considered best practice.
Risk-based next steps
These may include screening plans, referrals, and guidance on how to share results with relatives.
Not necessarily. It means risk is higher, and screening and prevention planning should be considered.
Screening recommendations still depend on age, sex, family history, and other risk factors. A negative result is not a universal clearance.
Hereditary variants affect all sexes. Men can carry and pass on variants, and some variants raise male cancer risks, such as prostate cancer, male breast cancer, pancreatic cancer, and melanoma.
No test can cover every genetic contributor, especially unknown ones. Even comprehensive panels have boundaries, and interpretation evolves.
The most accurate risk picture comes from combining:
Your genetic test result
Your personal health history
Your family history, including ages at diagnosis and cancer types
A result should rarely be interpreted in isolation.
Consider asking:
What cancers are most relevant to this gene result, if any?
How strong is the evidence for increased risk?
What screening schedule is supported by current guidelines?
Should relatives consider testing, and who should start?
Do any findings need re-checking or reclassification updates later?
How should my plan change based on family history, even if the test is negative?
Many people find it easier to plan next steps when they can talk through results with a genetic counselor and, if needed after a diagnosis, coordinate logistics and questions with a nurse navigator.
Variant classifications can change. Guidelines can change. Your personal risk changes with age and health factors. Plan to revisit your risk profile periodically, especially if your family history changes.
Genetic information is sensitive. People often worry about how results might affect insurance or employment. In the United States, the Genetic Information Nondiscrimination Act (GINA) offers protections in certain contexts, but it does not cover every type of insurance in every circumstance, and state laws vary.
Practical steps that help build trust:
Use services that follow medical privacy standards and clear consent practices
Understand who can access your results and under what conditions
Ask whether your data is shared, sold, or used for research, and how you can opt out if applicable
Genetic testing can identify inherited variants that increase the risk of certain cancers, clarify family risk, and support more personalized screening and prevention planning. It can also provide peace of mind for relatives when a known family variant is not present.
What it cannot do is predict your future with certainty, replace standard screening, or fully explain cancer risk when results are negative or uncertain. The most responsible use of genetic testing is as part of a larger health conversation, ideally supported by licensed professionals and ongoing clinical guidance.
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