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FeedbackFluorescence in situ Hybridization (FISH)
- Recommended FISH panel for adults with newly diagnosed B-ALL
- Probes include MYC rearrangement, BCR-ABL1 t(9;22), KMT2A (MLL) 11q23 rearrangement, IGH rearrangement, TCF3 (E2A) rearrangement
Fluorescence in situ Hybridization (FISH)
- Recommended FISH panel for children with newly diagnosed B-ALL
- Probes include CEP4, CEP10, BCR-ABL1 t(9;22), KMT2A (MLL) 11q23 rearrangement, ETV6-RUNX1 t(12;21), TCF3 (E2A)
Fluorescence in situ Hybridization (FISH)
- Used for diagnosis, prognosis, and monitoring of BCR-ABL1-like B-ALL
- Probes include CRLF2 rearrangement/partial deletion, ABL2 rearrangement, PDGFRB rearrangement, IKZF1 deletion, JAK2 rearrangement, ABL1 rearrangement, EPOR rearrangement
- Order when other major prognostic markers (e.g., BCR-ABL1, ETV6-RUNX1) are negative
Testing Strategy
At diagnosis, the minimum ALL workup includes bone marrow aspirate for morphology, immunophenotyping, cytogenetics (e.g., karyotyping and FISH), and other molecular testing, as indicated.
Acute lymphoblastic leukemia (ALL) is an aggressive leukemia of B- or T-lineage immature lymphoid cells. B-cell ALL (B-ALL) is primarily a disease of early childhood. Fluorescence in situ hybridization (FISH) testing identifies rearrangements in specific genes used in risk stratification and treatment decisions for children and adults newly diagnosed with B-ALL.
Disease Overview
Incidence
ALL occurs in an estimated 1.38-1.8/100,000 individuals per year in the United States. It is the most common leukemia in childhood. ,
Symptoms
Clinical manifestations are often nonspecific and may include fatigue, lethargy, dyspnea, dizziness, infections, and easy bruising or bleeding. Constitutional symptoms such as night sweats, fever, and unintentional weight loss may also occur. In children, joint and/or extremity pain may be the sole presenting symptom. ,
Genetics
| Pediatric ALL | Adult ALL | Ph-Like ALL |
|---|---|---|
CEP4 CEP10 BCR-ABL1 KMT2A (MLL) ETV6-RUNX1 TCF3 (E2A) | MYC BCR-ABL1 KMT2A (MLL) IGH TCF3 (E2A) | CRLF2 ABL2 PDGFRB IKZF1 JAK2 ABL1 EPOR |
| Ph, Philadelphia chromosome | ||
Test Interpretation
Test Results
Pediatric FISH
- Normal: no evidence of copy number gain with CEP4 and/or CEP10, BCR-ABL1 t(9;22), KMT2A (MLL) rearrangement, ETV6-RUNX1 t(12;21), RUNX1 deletion, RUNX1 amplification, or TCF3 (E2A) rearrangement
- Abnormal: at least one of the above rearrangements, translocations, or copy number changes detected
Adult FISH
- Normal: no evidence of MYC rearrangement, BCR-ABL1 t(9;22), KMT2A (MLL) rearrangement, IGH rearrangement, or TCF3 (E2A) rearrangement
- Abnormal: one of the above rearrangements or translocations detected
Ph-Like ALL FISH
- Normal: no evidence of CRLF2 rearrangement/partial deletion, ABL2 rearrangement, PDGFRB rearrangement, IKZF1 deletion, JAK2 rearrangement, ABL1 rearrangement, or EPOR rearrangement
- Abnormal: one of the above rearrangements and/or deletions detected
Prognostic Issues
More information on the prognostic significance of identified genetic rearrangements can be found in the ARUP Consult Acute Lymphoblastic Leukemia - ALL topic.
Limitations
Panels detect only the specific aberrations targeted by the FISH probes included. Chromosome alterations outside the regions complementary to these probes will not be detected.
References
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NCCN - pediatric acute lymphoblastic leukemia v1.2026
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: pediatric acute lymphoblastic leukemia. Version 1.2026. Accessed Apr 2026.
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NCCN - acute lymphoblastic leukemia v2.2025
National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: acute lymphoblastic leukemia. Version 2.2025. Accessed Apr 2026.