The short answer
In cancer care, genetic testing often means testing inherited DNA to learn about cancer risk in a person or family. Genomic testing, tumor genetic testing, or biomarker testing usually means testing cancer cells for changes that may guide treatment. The words are confusing because both involve genes, but the questions are different.
Inherited genetic testing looks for cancer risk changes you were born with.
Tumor genomic or biomarker testing looks for changes in cancer cells that may guide treatment.
One kind of test does not automatically replace the other.
Ask whether results could affect family members, treatment choices, or both.
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The full explanation.
The short answer
Both tests involve genes, but they answer different questions. Inherited genetic testing asks whether you were born with a DNA change that raises cancer risk. Tumor genomic testing, sometimes called biomarker testing, asks whether the cancer cells themselves have features that could guide treatment.
Inherited genetic testing, in practice
Inherited testing is usually done with a blood or saliva sample. It looks for germline variants, meaning DNA changes present in every cell of your body since birth, that can run in families. This kind of testing often involves a genetic counselor. They can explain what results could mean before the test, and help interpret them after. Results can affect your screening schedule, prevention options, surgery choices, and whether close relatives should consider testing too.
Tumor genomic or biomarker testing, in practice
Tumor testing looks at the cancer itself. It most often uses tissue from a biopsy, and sometimes a blood sample called a liquid biopsy. It may look for mutations, gene fusions, specific proteins, hormone receptors, or scores like microsatellite instability or tumor mutational burden. Each of these can help match your treatment to your cancer's specific biology. It's more precise than treating your cancer type as one uniform disease.
Why the words get mixed up
A tumor test report may use the word "genetic" simply because cancer cells have genetic changes. Those changes were not necessarily inherited. This is a common source of confusion at appointments. On the flip side, an inherited test result can still matter for family risk planning. This holds even when it does not choose your current treatment. Ask your team to clarify which kind of test you're discussing whenever the terms come up.
What each result can and cannot tell you
A tumor test result is specific to the sample taken. It can miss a change if the biopsy sample was too small. It can also miss a change if the cancer has changed since the sample was collected. An inherited test result is different. Once it's done, it typically does not change over time. It reflects DNA present in every cell.
What to ask next
Ask whether the sample tested is tumor tissue, blood for inherited DNA, or blood for a liquid biopsy test. Then ask what decisions the result could affect: your treatment, your family's risk, future screening, or all of the above.
Sources
Words to know
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Common questions
Is tumor genomic testing the same as inherited genetic testing?
No. Tumor testing looks at changes in cancer cells. Inherited testing looks for DNA changes present in the body from birth that may affect family risk.
Can a tumor test find something inherited?
Sometimes a tumor result raises the question of inherited risk, but a separate germline genetic test may be needed to answer that family-risk question.
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Sources last checked: 2026-07-19 what this meansLast updated: 2026-08-11Next planned review: 2027-07-19
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How this page was created
Cancer Explained does not originate medical claims. Every page restates guidance already published by the National Cancer Institute, the CDC, the USPSTF and the FDA, in plain language, with the source cited so you can check the original yourself. AI does the translating and organizing; automated checks test claims, citations, clarity and safety before anything publishes. We do not employ clinicians and do not intend to — our work is translation and navigation, not clinical judgment. Nothing here is personal medical advice, and no page can account for your particular situation.
Editorial status: Source checked — This page was written with AI assistance and checked line by line against the sources listed on it. That confirms the sources support what the page says. It is not a medical review, and it does not confirm the page is complete or right for your situation.
Human medical review: not completed. Pages here are not signed off by a clinician before they publish. That is not an oversight we are quietly working around: we restate published guidance and cite it, so the authority belongs to the source rather than to us, and every page names where its claims come from — you can verify us instead of trusting us. Where a volunteer clinician has reviewed a page, their name and credentials appear on it; where no name appears, no clinician has checked it. We are glad to have reviewers and are recruiting them, and we do not hold pages back waiting for one. Use this site to understand your situation and to ask better questions of the people treating you.
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