Cancer genetic tests fall into two main groups: hereditary (germline) tests look in a blood sample for inherited cancer-predisposition variants present from birth and guide risk management; tumour (somatic) tests examine the acquired mutations in tumour tissue or in tumour DNA in the blood that determine treatment. Both are planned with a physician's assessment.
The difference between hereditary and tumour testing
Although they are referred to in the same words, the two tests answer different questions. Hereditary testing addresses “Am I, or is my family, at risk?”, while tumour testing addresses “Which drug will this tumour respond to?”.
| Hereditary (germline) | Tumour (somatic) | |
|---|---|---|
| What does it look for? | Predisposition variants present from birth in every cell | Mutations that arise later in tumour cells |
| Sample | Blood | Tumour tissue (FFPE) or blood (ctDNA) |
| Who is it for? | Healthy individuals and patients; those with a family history | Patients diagnosed with cancer |
| What does it provide? | Screening and prevention plan, family screening, some treatment decisions | Eligibility for targeted drugs and immunotherapy, clinical trial matching |
| Lue GEN tests | OncoSeq® C / S / VS / X, ExoSeq® Onco, ExoSeq® GI | CanAct® X Solid, CanAct® X Liquid, EndoPredict® |
Who should have hereditary cancer testing?
Around 5–10% of cancers are linked to an inherited predisposition. Guidelines recommend hereditary testing in the following situations:
- Breast, colorectal or endometrial cancer at a young age (under 50)
- Ovarian, pancreatic or male breast cancer, or metastatic prostate cancer (at any age)
- More than one primary cancer in the same person
- Several related cancers on the same side of the family, or a known pathogenic variant
- A finding on tumour testing that may be hereditary
- Rare tumours: medullary thyroid cancer, phaeochromocytoma, retinoblastoma, sarcoma
Which test is chosen?
For hereditary risk, the breadth of the panel is determined by the family history. OncoSeq® C (12 genes) covers the genes most frequently linked to breast, ovarian and colorectal cancer; OncoSeq® S (25 genes) adds Lynch syndrome and other common syndromes; OncoSeq® X (50 genes) is the broadest panel and also includes rare syndromes. The exome-based ExoSeq® Onco (173 genes) and ExoSeq® GI (336 genes) are for cases that require very broad screening or in which previous panels gave no answer.
For patients who have already been diagnosed, CanAct® X profiles the tumour by examining 523 genes from a tissue or blood sample; in early-stage, hormone-receptor-positive breast cancer, EndoPredict® answers the question of whether chemotherapy is needed. The guide by cancer type on our Oncology page shows which test is used at which stage for each diagnosis.
How are the results interpreted?
A hereditary test report has three types of result. Positive: a pathogenic or likely pathogenic variant was found; risk is increased, and screening, prevention, treatment and family screening are planned accordingly. Negative: no known harmful variant in the genes examined; this does not mean you will never develop cancer, and standard screening continues. VUS: a variant of uncertain significance; it does not require action on its own and is reclassified as new evidence emerges.
A tumour test report, by contrast, ranks each alteration detected by level of evidence: those matching an approved drug, those included in guidelines and those under investigation in clinical trials are listed separately. This report is prepared to help your oncologist shape the treatment plan.
How does the process work?
When you submit an appointment request, our team calls you within one working day at the latest; we listen to your family history or diagnosis, obtain your physician's referral if there is one, and clarify the sample type. Blood samples are collected at Akasya Partner Clinics; for tissue tests, the pathology block is collected by courier. Analyses are performed in our CAP-accredited, ISO 15189-certified partner laboratory; depending on the test, the report is ready in 1–6 weeks and is interpreted together with our consultant physicians. Pre- and post-test genetic counselling is part of the process.
Frequently asked questions
Does cancer genetic testing diagnose disease?
Hereditary tests do not make a diagnosis; they provide information about risk. Tumour tests describe the molecular features of an existing cancer; the diagnosis is made by pathology, and the test guides the choice of treatment.
Do I need to have been diagnosed with cancer to have hereditary testing?
No. Healthy individuals with a family history can also be tested; in fact, testing an affected family member first makes it possible to screen other relatives specifically for the known variant.
How reliable is the test result?
In hereditary panels run by next-generation sequencing, analytical accuracy for the regions examined is above 99%. The limitation lies in interpretation: each variant is classified according to ACMG rules, and those that remain VUS are re-evaluated over time.
Who can see my results?
Only you and the physician you authorise. Under KVKK (Turkish Personal Data Protection Law), genetic data are classed as special categories of personal data and are not shared without your explicit consent.