This map explains inherited (hereditary) cancer and genetic testing: who should be tested, how it is done, and what the results mean.
Tap any topic on the map to read about it. Topics with an arrow open more topics.
Most cancers happen by chance, from mutations that build up in one part of the body during life. These are not passed on to children.
About 5 to 10 out of 100 cancers are linked to an inherited mutation: a change in a gene that is present from birth in every cell of the body.
It can come from either the mother or the father. Each child of a carrier has a 1 in 2 chance of inheriting it.
Carrying a mutation means a higher risk, not a certainty. Many carriers never get cancer, and screening and prevention lower the risk further.
Tap a group on the map.
Why this matters: finding a mutation can change your treatment, and protect your family.
Breast cancer at 50 or younger, triple-negative breast cancer, or breast cancer in a man.
Ovarian, fallopian tube or peritoneal cancer at any age.
Pancreatic cancer at any age.
Prostate cancer that has spread, or is high risk.
Bowel or womb cancer under 50, or when the tumour shows MMR deficiency.
Two or more separate cancers in the same person.
A sarcoma, adrenal cancer, medullary thyroid cancer or phaeochromocytoma.
A known mutation in the family: the simplest and cheapest test.
A strong family history: several relatives on the same side with breast, ovarian, bowel, womb, pancreatic or prostate cancer, especially at a young age.
When possible, the relative who has had cancer is tested first, as their result is the most informative.
A discussion before the test: what the test can and cannot show, what a result would mean for you and your family, and how you may feel about it.
A discussion after the result: what it means, the screening and prevention plan, and which relatives should be tested.
Genetic results affect the whole family, so this time to understand and ask questions is as important as the test itself.
Your oncologist will do this with you, and may involve a trained genetic counsellor.
Usually a panel that checks many cancer genes at once (BRCA1, BRCA2, the Lynch genes, PALB2, TP53 and others).
If a mutation is already known in the family, only that one change is checked (a single-site test), which costs much less.
Results take about 2 to 4 weeks.
Inherited (germline) test
Tumour NGS
Sample
Blood or saliva
Cancer tissue (biopsy) or blood
What it finds
Mutations you were born with, present in every cell
Mutations in the cancer only, mostly acquired during life
Passed to family?
Yes, possibly
Usually no
Main use
Your future risk, prevention, family testing, and some treatment choices
Treatment choices in advanced cancer
Sometimes tumour NGS finds a mutation (for example in BRCA2) that may be inherited. Then a blood test is advised to check.
The result can change the surgery (for example mastectomy instead of lumpectomy, or removing the ovaries) and the medicines (such as PARP tablets or immunotherapy).
When the result could change the operation, we sometimes ask for it quickly, before surgery.
Relatives should wait for the confirmed report before planning their own tests.
There are three kinds of result. Tap one on the map.
A harmful (pathogenic or likely pathogenic) mutation was found.
Your doctor will explain the cancer risks, a screening and prevention plan, and which relatives should be tested.
If a mutation is known in your family and you do not have it: a true negative. Your risk is like anyone else's, and your children cannot inherit it from you.
If no mutation is known in the family: reassuring, but it does not rule out all inherited risk. Screening may still be based on your family history.
A variant of uncertain significance: a change whose meaning is not yet known. It is common.
Most VUS are later found to be harmless. A VUS is treated like a negative result.
Decisions such as surgery are not based on a VUS, and relatives are not tested for it.
Laboratories update the result as more is learned; ask about it at follow-up.
Cost: the first panel test is expensive, but testing relatives for a known mutation costs much less.
Marriage and stigma: a mutation is nobody's fault. Talking openly, with your doctor's help, usually brings families together rather than apart.
Insurance: India has no specific law on genetic discrimination. Discuss any concern with us before testing.
Fear of the result: knowing allows you to act early. Many carriers stay well because of screening and prevention.
This information is general. Your own treatment plan may be different. Please discuss it with your doctor.
Written and medically reviewed by Dr Prathyusha Eaga, MD, DM (Medical Oncology). Last reviewed: 12 October 2026. Based on NCCN and ESMO guidelines.
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Cancer types