Test ID: TALLF    
T-Cell Acute Lymphoblastic Leukemia (T-ALL), FISH, Varies

Detecting a neoplastic clone associated with the common chromosome abnormalities seen in patients with T-cell acute lymphoblastic leukemia (T-ALL)

Identifying and tracking known chromosome abnormalities in patients with T-ALL and tracking response to therapy

An adjunct to conventional chromosome studies in patients with T-ALL

This test includes a charge for application of the first probe set (2 FISH probes) and professional interpretation of results. Additional charges will be incurred for all reflex probes performed. Analysis charges will be incurred based on the number of cells analyzed per probe set. If no cells are available for analysis, no analysis charges will be incurred.

We recommend the following testing algorithm for patients with T-cell acute lymphoblastic leukemia (T-ALL):

-At diagnosis, conventional cytogenetic studies (CHRBM / Chromosome Analysis, Hematologic Disorders, Bone Marrow) and a complete T-ALL FISH panel should be performed.

-At follow-up, conventional cytogenetic studies (CHRBM / Chromosome Analysis, Hematologic Disorders, Bone Marrow) and targeted T-ALL FISH probes based on the abnormalities identified in the diagnostic study can be evaluated.

-If the patient clinically relapses, a conventional chromosome study is useful to identify cytogenetic changes in the neoplastic clone or the possible emergence of a new therapy-related myeloid clone.

Panel includes testing for the following abnormalities using the probes listed:

1p33 rearrangement, TAL1/STIL

t(5;14) TLX3/BCL11B

7q34 rearrangement, TRB

9p-,CDKN2A/D9Z1

t(9;22) or ABL1 amplification, BCR/ABL1

t(10;11), MLLT10/PICALM

11q23 rearrangement, MLL (KMT2A)

14q11.2 rearrangement, TRAD

17p-, TP53/D17Z1

When an MLL (KMT2A) rearrangement is identified, reflex testing will be performed to identify the translocation partner. Probes include identification of t(4;11)(q21;q23) AFF1/MLL, t(6;11)(q27;q23) MLLT4/MLL, t(9;11)(p22;q23) MLLT3/MLL, t(10;11)(p13;q23) MLLT10/MLL, t(11;19)(q23;p13.1) MLL/ELL or t(11;19)(q23;p13.3) MLL/MLLT1.

When a TRAD rearrangement is identified, reflex testing will be performed to identify the translocation partner. Probes include identification of t(8;14)(q24.1;q11.2) MYC/TRAD, t(10;14)(q24;q11.2) TLX1/TRAD, t(11;14)(p15;q11.2) LMO1/TRAD or t(11;14)(p13;q11.2) LMO2/TRAD.

When a TRB rearrangement is identified, reflex testing will be performed to identify the translocation partner. Probes include identification of t(7;10)(q34;q24) TRB/HOX11, t(7;11)(q34;p15) TRB/LMO1, t(7;11)(q34;p13) TRB/LMO2, or t(6;7)(q27;q34) TRB/MYB.

In the absence of BCR/ABL1 fusion, when an extra signal for ABL1 is identified, reflex testing will be performed using the ABL1 break-apart probe set to evaluate for the presence or absence of an ABL1 rearrangement.

If this test is ordered and the laboratory is informed that the patient is on a COG protocol, this test will be canceled and automatically reordered by the laboratory as COGTF / T-Cell Acute Lymphoblastic Leukemia (T-ALL), Children’s Oncology Group Enrollment Testing, FISH, Varies.

Fluorescence In Situ Hybridization (FISH)