Quick Answer
Why two patients with the same cancer can need different treatment — and how molecular testing answers that question.
Medically reviewed by Dr. Sachita Baniya • NMC 20158 • Kathmandu Neurology Clinic & Cognitive Center
Blood cancers that look similar under the microscope can behave very differently. Molecular testing explains part of that difference by identifying mutations, fusions and chromosomal changes that affect prognosis and treatment.
The main types of test
- Karyotype: examines chromosomes for rearrangements, deletions and additions.
- FISH: targets specific genes or regions with fluorescent probes.
- PCR: detects specific fusion transcripts or mutations with high sensitivity.
- Next-generation sequencing: tests many genes at once.
Examples of clinical impact
In AML, NPM1, FLT3, IDH1/2, CEBPA and TP53 results influence risk and targeted therapy. In CML, BCR-ABL1 monitoring guides TKI therapy. In CLL, TP53 status affects treatment choice. In myeloma, FISH identifies high-risk disease. In MDS, cytogenetics and molecular findings refine prognosis.
What a variant of uncertain significance means
Not every genetic change has a known clinical effect. A variant of uncertain significance should not be over-interpreted or used alone to make treatment decisions. Specialist review and, sometimes, repeat testing are needed.
When testing is repeated
Testing may be repeated when the disease progresses, response is poor or resistance is suspected. Cancers evolve, and a new mutation can change the treatment options.
Practical questions
- Which result changed my diagnosis or risk group?
- Does the result make a targeted therapy available?
- Will this test be used to monitor my response?
- What does an uncertain result mean for my care?
The bottom line
Molecular testing is now part of standard care for many blood cancers. It should be interpreted with morphology, flow cytometry and clinical context — not in isolation.
Frequently asked questions
Answers reviewed by Dr. Jitendra Prasad Yadav • MBBS, MD (Internal Medicine), FICN (Neurology), FCNV, FIHM • NMC 8029
AML can be cured in a proportion of patients, particularly younger adults who achieve remission and proceed to appropriate consolidation or transplant. Outcomes vary widely with genetic subtype, age and fitness, so the treating team discusses prognosis for the individual case rather than giving a single figure.
Induction is the first phase of treatment, aiming to clear leukemia cells from the marrow and restore normal blood production. It usually requires hospital admission and close support with transfusion, infection prevention and monitoring.
CML is usually controlled long term with tyrosine kinase inhibitors rather than cured in the traditional sense. Some patients achieve sustained deep molecular responses and may be considered for treatment-free remission under close supervision.
Monitoring is usually performed at 3, 6 and 12 months after starting therapy, then periodically once a stable response is achieved. The exact schedule depends on the response and any treatment changes.
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References & Review
Reviewed by Dr. Jitendra Prasad Yadav • Last reviewed: 2026-11-10
- International Classification of Headache Disorders, 3rd edition (ICHD-3).
- Harrison's Principles of Internal Medicine — Neurology sections.
- American Academy of Neurology guidelines for selected conditions (where applicable).
Content is educational and aligns with standard medical references; individual evaluation may vary. External links provide context and do not imply endorsement.