Key Takeaways
- A gene name is not a prescription. The exact alteration, cancer type, disease setting, assay and treatment indication all matter.
- “No mutation found” may mean no alteration in the tested regions, too little tumour, poor sample quality or too little tumour DNA in plasma. Read the limitations before calling a result negative.
- Tissue and liquid biopsy answer overlapping but not identical questions. A negative plasma result may need tissue confirmation when feasible.
- Variants of uncertain significance should not be treated as actionable findings. A possible inherited result needs separate germline confirmation and counselling.
- Targeted therapy still requires toxicity monitoring and a plan for resistance. “Precision” does not mean risk-free or permanently effective.
Content
Targeted therapy is often described as matching one mutation to one drug. Real decisions are less tidy. A tumour sample may be old or small, a test may not cover the relevant alteration, the same gene may contain both sensitive and resistant variants, and a drug approved in one cancer may have little evidence in another. The useful chain is:
clinical question → suitable specimen → validated assay → interpretable result → cancer-specific evidence → treatment and monitoring plan.
If any link is missing, a colourful sequencing report can look more certain than it is.
Define the question before ordering the test
Biomarker testing for treatment looks for genes, proteins or other tumour features that may guide therapy. It is not the same as hereditary cancer testing, and it is not the same as using a blood tumour marker to monitor disease.[1] Before paying for a panel, ask what decision the result could change now.
The answer may be narrow: confirm HER2 status before a particular therapy, look for a known resistance mutation, or establish whether a tumour meets an approved companion-diagnostic definition. A broad next-generation sequencing panel may be reasonable in another setting, but “more genes” does not automatically produce more useful answers. The panel's coverage, alteration types, specimen requirements and clinical evidence are more important than the headline number.
China's 2025 national guidance for novel antineoplastic drugs places pathological confirmation, required target testing, adherence to indications and management of adverse reactions among its basic principles.[2] The national cancer-quality action plan likewise states that drugs with a defined target should have testing support.[3] Testing should therefore follow the diagnosis and the treatment question, not replace them.
Identify what was actually tested
Keep the complete laboratory report, requisition and pathology context. A usable report should let another team answer:
- Which block, slide, marrow, blood or other specimen was analysed, and when was it collected?
- Was the specimen from the primary tumour or a metastasis, before or after important treatment?
- Did a pathologist assess tumour content and sample adequacy?
- Was the method immunohistochemistry, in-situ hybridisation, PCR, sequencing or another validated assay?
- Which genes, exons, variants and alteration classes were covered—single-nucleotide variants, insertions/deletions, copy-number changes, fusions, protein expression or genomic signatures?
- What were the quality metrics and detection limit, and did the laboratory issue any limitation or failed-test comment?
- Is the reported finding pathogenic, likely pathogenic, uncertain, likely benign or benign, and what evidence tier supports the treatment association?
“EGFR negative” is incomplete if the reader cannot tell whether the assay covered sensitising mutations, resistance mutations and the relevant specimen type. “HER2 positive” is incomplete without the cancer context, method and scoring. A report that lists a gene but not the exact variant may not support safe prescribing.
Tissue versus liquid biopsy: choose deliberately
Tissue shows tumour architecture and enables pathology, immunohistochemistry and many molecular tests, but tissue may be old, exhausted or unsafe to obtain. A liquid biopsy samples circulating tumour material through blood and can be useful when a tumour biopsy is difficult or when current resistance is being investigated.[1] It does not guarantee that every tumour site sheds enough DNA into plasma.
The interpretation is asymmetric: a well-validated positive result may be actionable in the correct context, while a negative plasma result may be uninformative. Current FDA labelling for an authorised plasma companion diagnostic explicitly says that a negative plasma result does not assure the tumour is negative and recommends tissue testing for listed biomarkers when feasible.[4] Ask the oncologist whether “nothing detected” means the search can stop or whether a recent tissue sample is still needed.
Also ask whether the blood test sequences white-cell DNA or otherwise addresses clonal haematopoiesis, which can introduce non-tumour variants into plasma results. If the report raises a possible inherited alteration, tumour profiling alone does not establish that the change is germline. NCI recommends confirmatory hereditary testing and genetics support when an inherited finding is suspected.[1]
Translate the result without jumping straight to a drug
Use five filters for every reported “match”:
- Alteration: Is it the exact variant, fusion, amplification, expression threshold or signature associated with benefit?
- Cancer context: Does evidence apply to this tumour type and histology, or is it extrapolated from another disease?
- Disease setting: Is the treatment approved or recommended at this stage and line, after these prior therapies?
- Test relationship: Does the drug label require a particular companion diagnostic, specimen or threshold?
- Clinical fit: Do organ function, other illnesses, interactions, prior toxicity and patient goals make the drug reasonable?
A variant of uncertain significance is not a treatment target. NCI notes that benign changes and variants of unknown significance are not used to make treatment decisions.[1] A computer-generated “potential therapy” may refer to a preclinical study, early trial, off-label use or an approved indication; those categories must not be collapsed.
Companion diagnostics illustrate why the assay–drug link matters. FDA's current list maps an authorised diagnostic, cancer and specimen type, biomarker details and corresponding medicine rather than treating all tests for one gene as interchangeable.[5] China's device-review guidance for companion diagnostics likewise requires consistency in the biomarker, status classification, intended population, specimen type and analytical performance when comparing a non-original test with the original companion diagnostic.[6]
Decide whether an off-label match or trial is worth pursuing
When a finding has no standard approved match in the patient's cancer, ask the molecular tumour board or treating oncologist to state the evidence level, expected benefit, known resistance features and the standard alternatives. Tissue-agnostic approvals do exist, but they have precise biomarker and clinical conditions; they do not establish that every rare variant in the same gene should be treated similarly.
For a clinical trial, verify the registry entry, recruiting site, molecular eligibility, confirmatory test, washout period and who pays for screening and treatment. “Trial available” on a commercial report may refer to a distant or closed site. Do not travel until the study site has reviewed the actual records and issued a pre-screening response.
Build the treatment plan around the medicine, not the word “targeted”
Most targeted therapies are small molecules or monoclonal antibodies.[7] Their risks vary: rash, diarrhoea, liver injury, hypertension, bleeding, heart dysfunction, lung inflammation, eye problems and many other effects are drug-specific. Some oral agents have important food, acid-suppressing medicine or CYP enzyme interactions. Ask for the official product, generic name, dose, schedule, interaction review, baseline tests, monitoring frequency, dose-modification rules and urgent symptoms.
The price comparison should include the test, pathology review, specimen retrieval or re-biopsy, confirmatory assay, medicine, laboratory and imaging monitoring, and treatment of toxicity. If a product available in China is not sold in the home country, establish how a continuous lawful supply and follow-up will work before starting it.
Plan now for the moment the therapy stops working
Some tumours never respond despite an apparently valid match; others initially shrink and later develop resistance. Resistance may occur because the target changes or because cancer cells find a different growth pathway.[7][8] Before treatment begins, agree on the response-assessment date and define what counts as benefit, unacceptable toxicity and progression.
At progression, do not automatically repeat the identical old panel on the identical old specimen. Ask whether a new tissue or plasma test could identify an acquired resistance mechanism and whether the result would change the next choice. Sometimes the most useful conclusion is that no established targeted option exists; that is more honest than turning an uncertain variant into a promise.
For cross-border handover, retain the pathology report, specimen identifiers, full assay report and coverage, molecular interpretation, prescription and dose history, toxicity, response scans and reason for stopping. A screenshot of the “actionable” page is not enough for another oncologist to audit the decision.
Medical disclaimer: This guide is educational and does not interpret an individual genomic report or recommend a targeted medicine. Biomarker results must be integrated with pathology, cancer setting, drug labelling, clinical evidence and patient factors by qualified oncology and laboratory professionals.
Related Hospitals
List only centres whose tumour-specific service, pathology or molecular laboratory, multidisciplinary interpretation and access to the proposed medicine have been verified.
Related Treatments
Link a medicine only after checking the exact alteration, approved or evidence-supported setting, current availability and clinical eligibility.
Related Guides
- Pathology review and tissue preservation
- Cancer second opinions
- Clinical-trial searching in China
- Oral anticancer medicine safety
FAQ
Does finding a mutation mean there is a targeted drug for it?
No. The exact alteration may be non-driving, uncertain, resistant to a drug, unsupported in that cancer or matched only to a research study. The report must be interpreted in the tumour and treatment context.
Is a large NGS panel always better than a small test?
No. A focused validated test may answer the immediate treatment question. A broad panel is useful only if it adequately covers relevant alteration types, has sufficient sample quality and produces results that can change care.
What does a negative liquid biopsy mean?
It may mean no covered alteration was detected, but it can also reflect insufficient tumour DNA in blood. For authorised companion-diagnostic uses, FDA labelling warns that a negative plasma result does not prove the tumour is negative and recommends tissue confirmation when feasible.[4]
Can a tumour test reveal an inherited cancer risk?
It may raise suspicion, but tumour profiling is not a substitute for germline testing. A possible inherited finding should be confirmed using an appropriate normal sample with genetics counselling, because it may affect relatives.[1]
Why repeat testing when the cancer progresses?
Tumour biomarkers can change, and treatment can select resistant clones. A new tissue or plasma sample may reveal an acquired resistance mechanism—but retesting is useful only when the result could alter the next decision.[1][8]
Sources
- US National Cancer Institute — Biomarker Testing for Cancer Treatment
- National Health Commission of China — Guidelines for Clinical Application of Novel Antineoplastic Drugs (2025 Edition)
- National Health Commission of China — Action Plan to Improve the Quality of Cancer Diagnosis and Treatment
- US FDA — Guardant360 CDx Premarket Approval and Current Labelling
- US FDA — List of FDA-Authorized Companion Diagnostic Devices
- China NMPA Center for Food and Drug Inspection — Registration Review Guideline for Non-Original Companion Diagnostics
- US National Cancer Institute — Targeted Therapy to Treat Cancer
- US National Cancer Institute — Why Cancer Treatments Stop Working
Hero Image Review
- Decision: Rejected; replacement pending as hero-reviewed.png.
- Why: DNA and target icons decorate another generic consultation scene but do not show a specimen, laboratory method, report interpretation or drug-matching decision.
- Replacement brief: Documentary 16:9 laboratory consultation: a molecular pathologist and oncologist compare a de-identified, unreadable biomarker report with clearly differentiated tissue-block and blood-tube sample types; no patient identifiers, legible variants, oversized DNA helix, glowing target symbols, logos or futuristic interface.