Overview: FISH t(12;21) TEL AML1 Panel
Introduction: The FISH t(12;21) TEL AML1 Panel is a diagnostic tool designed to detect t(12;21) in leukemia using whole blood or bone marrow samples. In India, t(12;21)(p13;q22) TEL/AML1 (ETV6/RUNX1) fusion occurs in ~20-25 percent of childhood B-cell acute lymphoblastic leukemia (ALL), associated with favorable prognosis and excellent cure rates with standard chemotherapy. High morbidity from under-testing in rural/low-SES pediatric leukemia patients, limited FISH labs, delayed risk-adapted therapy leading to overtreatment or relapse. Per cytogenetics practices aligned with ICMR and Indian Society of Pediatric Hematology Oncology guidelines, the test employs FISH for TEL/AML1 translocation over 1-2 days with high sensitivity/specificity, valuable for molecular subtyping and favorable-risk classification in childhood ALL. This diagnostic falls under genetic cancer screening and targets children with B-ALL, addressing accurate detection to guide chemotherapy intensity and monitoring. With elevated morbidity due to under-testing, the test supports public health efforts by enabling precise molecular diagnosis and improving pediatric leukemia survival. Its blood/bone marrow-based approach ensures reliable fusion detection.
Other Names: FISH t(12;21) Pnl.
FDA Status: FDA approved, CLIA certified for cytogenetics/oncology, compliant with 2025 standards.
Historical Milestone: TEL/AML1 FISH favorable marker; in India, used in pediatric ALL protocols.
Purpose: The test detects 2 parameters including TEL/AML1 translocation to guide leukemia genetic assessment, identify favorable-risk feature, inform therapy.
Test Parameters: 1. TEL/AML1 Translocation, 2. Chromosomal Rearrangement.
Pretest Condition: No fasting required; patients should have confirmed B-ALL.
Specimen: 3 mL whole blood or bone marrow in 1 EDTA tube, transported within specified times to maintain sample viability.
Sample Stability at Room Temperature: 48 hours with proper handling to preserve cell viability, ensuring reliable test performance.
Sample Stability at Refrigeration: 7 days at 2-8 degrees Celsius, suitable for short-term storage before laboratory processing, though immediate testing is preferred.
Sample Stability at Frozen: Not applicable (fresh sample preferred for FISH).
Medical History: Patients should provide details on ALL subtype, age, WBC count, prior therapy.
Consent: Written informed consent is required, detailing the test's purpose, potential risks of undetected favorable abnormality including overtreatment, benefits of detection, and minimal discomfort from blood/bone marrow draw.
Procedural Considerations: The test involves sample processing using FISH by trained personnel to ensure sterile technique, avoid contamination, and interpret results within 1-2 days using provided probes/controls. Laboratories must maintain a controlled environment, adhere to quality assurance protocols.
Factors Affecting Result Accuracy: Delays beyond stability periods, improper storage conditions, or low blast count can affect results. Correlation with clinical evaluation or additional testing is recommended to confirm findings.
Clinical Significance: Positive TEL/AML1 indicates favorable ALL prognosis, necessitating specialist input. Negative may require follow-up.
Specialist Consultation: Pediatric oncologists should be consulted for management.
Additional Supporting Tests: Karyotype, NGS for confirmation.
Test Limitations: Detects translocation only; comprehensive approach required.
References: Indian Journal of Pediatrics 2024, ALL Studies India 2023.
