Leukemia Biomarkers
BCR-ABL1 — the Philadelphia chromosome — defines CML and was the first major precision oncology target: imatinib (Gleevec) transformed CML from a fatal disease into a manageable condition.
Reviewed by XpertPatient Medical Advisory · Updated June 2026 · Sources: NCI · ACS · ASCO · NIH/PMC
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What is a biomarker?
A biomarker in leukemia is usually a specific gene change in your blood or bone marrow cells. These genetic changes define what type of leukemia you have — and which treatments are designed to target it.
Leukemia was one of the first cancers where doctors discovered a specific gene change — and built a drug to block it. The drug imatinib (Gleevec), developed to target BCR-ABL1 in CML, transformed that disease from a death sentence into a manageable condition. Genetic testing is now the foundation of every leukemia diagnosis.
What this means for you: Your specific gene changes determine your leukemia type, your prognosis, and which drugs are most likely to work. Two people with ‘leukemia’ may need completely different treatments.
The Tests Your Doctor Orders
🔍 Is there a specific gene fusion that defines your CML?
BCR-ABL1 is the signature mutation of chronic myeloid leukemia (CML). Imatinib (Gleevec) was designed specifically to block it — and it works so well that many CML patients now live normal lifespans. BCR-ABL1 levels are monitored throughout treatment to track response.
🔍 Is there a mutation that makes AML more aggressive?
FLT3 mutations are found in 25–30% of AML cases and are linked to higher relapse risk. Drugs like midostaurin and gilteritinib target FLT3 directly and improve outcomes when added to treatment.
🔍 Is there a mutation that’s actually a good sign?
NPM1 mutations — when found without a FLT3 mutation — are a favorable sign in AML. Patients with this profile tend to respond well to standard chemotherapy and have better outcomes.
Watch & Learn
Common Questions
Leukemia Biomarkers — Your Questions Answered
How is CML different from AML?
CML is driven by BCR-ABL1 and treated with daily oral pills called TKIs. AML is more aggressive and treated with intensive chemotherapy. They are different diseases with different genetic drivers and completely different treatments.
How often is BCR-ABL1 monitored in CML?
Every 3 months for the first 2 years, then every 3–6 months after that. The goal is for BCR-ABL1 to become undetectable. Some patients who achieve this for long enough may eventually be able to stop treatment.
What if CML stops responding to imatinib?
The cancer has likely developed a resistance mutation. Your doctor will test for this, then switch to a different TKI — like dasatinib, nilotinib, or ponatinib — that can overcome the resistance.
Can leukemia be cured?
It depends on the type. Many CML patients achieve lasting remission. AML can be cured in some patients, especially younger patients and those with favorable genetics. A stem cell transplant may be recommended for higher-risk cases.
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