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Acute Leukemia Translocation Panel Screen By Nanofluidics

Indication

The current World Health Organization classification of hematopoietic and lymphoid tissues (WHO Classification of Tumors, 4th ed., 2008) defines distinct subtypes of acute myeloid leukemia (AML) and B lymphoblastic leukemia (previously B-ALL) based on the presence of recurrent reciprocal chromosomal translocations that produce fusion proteins associated with oncogenesis. For example, t(8;21)(q22;q22), inv(16)(p13.1q22), t(15;17)((q22;q12) in AML and t(12;21)(p13;q22) in B-lymphoblastic leukemia are generally associated with a favorable prognosis, while t(9;22)(q34;q11.2), in B-lymphoblastic leukemia portends a poor outcome. Therapeutic approaches may be tailored according to the presence or absence of one of these disease-associated translocations. For example, targeted therapies already exist for treatment of B-lymphoblastic leukemia with t (9;22) (imatinib) and AML with t(15;17) (all-trans retinoic acid or ATRA). Significantly, the minimum blast count requirement of 20% for the diagnosis of AML is waived when one of the predefined recurrent balanced translocation is present. Testing for the presence of these recurrent translocations at diagnosis for accurate diagnostic subclassification and, therapeutic and prognostic stratification has become a standard of care. A reverse transcriptase (RT)-PCR-based clinical assay utilizing a combination of nanofluidics-based integrated fluidics circuits and Taqman probes has been developed by the molecular diagnostics laboratory (MDL) to screen for 14 leukemia-related fusion transcripts in acute leukemias. This assay will replace the currently used microsphere-based multiplex PCR translocation detection assay at the MDL.

Methodology

Acute leukemia-associated fusion transcripts are tested using nanofluidics-based qualitative multiparametric reverse-transcriptase PCR.

Test Parameters

The current panel of fusion genes interrogated includes: t(8;21)(q22;q22); RUNX1-RUNX1T1, inv(16)(p13.1q22) or t(16;16)(p13.1q22); CBFβ-MYH11 variant A, inv(16)(p13.1q22) or t(16;16)(p13.1q22); CBFβ-MYH11 variant D, inv(16)(p13.1q22) or t(16;16)(p13.1q22); CBFβ-MYH11 variant E, t(15;17)(q22;q12); PML-RARA long form, t(15;17)(q22;q12); PML-RARA short form, t(15;17)(q22;q12); PML-RARA alternative form, t(9;22)(q34;q11.2); BCR-ABL1 b2a2, t(9;22)(q34;q11.2); BCR-ABL1 b3a2, t(9;22)(q34;q11.2); BCR-ABL1 e1a2, t(12;21)(p13;q22); ETV6-RUNX1, t(1;19)(q23;p13.3); E2A-PBX1, t(4;11)(q21;q23); MLL-AF4, and t(6;9)(p23;q34); DEK-CAN. The lower limit of detection is approximately 1 I 1000 to 1 in 10000 depending upon the fusion transcript.

Turnaround Time

5 working days

Sample Requirements

Bone marrow (2-5ml) or peripheral blood (10ml) specimen collected in EDTA (purple - top tube) sent on wet ice.

CPT Codes

81206; 81207; 81315, 81401 (x5); 81479.

The CPT codes provided are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.


© 2014 The University of Texas MD Anderson Cancer Center