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Test ID TALAF T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), FISH, Adult, Varies


Ordering Guidance


This test is only performed on specimens from patients with T-cell acute lymphoblastic leukemia (T-ALL) who are 31 years and older.

 

This test is intended for instances when the entire T- ALL fluorescence in situ hybridization (FISH) panel is needed for an adult patient.

-If this test is ordered on a patient 30 years of age or younger, this test will be canceled and automatically reordered by the laboratory as TALPF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), FISH, Pediatric, Varies.

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

-If BALAF / B-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), Adult, FISH, Varies is ordered concurrently with this test, the laboratory may cancel TALAF and automatically reorder as TALMF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), Specified FISH, Varies with the following FISH probes: TLX3/BCL11B, break-apart TRB, break-apart TRAD, MLLT10/PICALM, TAL1/STIL. If an abnormality is identified that would result in reflex testing in TALAF, the same reflex testing will be performed in the TALMF. This cancellation is necessary to avoid duplicate testing. Probes for break-apart PDGFRB, break-apart JAK2, CDKN2A/D9Z1, ABL1/BCR, break-apart ABL1, break-apart MLL, TP53/D17Z1 will still be performed as part of the adult B-ALL FISH panel.

If limited T-cell ALL FISH probes are preferred, order TALMF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), Specified FISH, Varies.

 

At follow-up, conventional cytogenetic studies (CHRBM / Chromosome Analysis, Hematologic Disorders, Bone Marrow) and targeted T-ALL FISH probes can be evaluated based on the abnormalities identified in the diagnostic study. Order TALMF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), Specified FISH, Varies and request specific probes or abnormalities.

 

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.

 

For patients with T-cell lymphoma, order TLPDF / T-Cell Lymphoma, Diagnostic FISH, Varies.

 

For testing paraffin-embedded tissue samples from patients with T-cell lymphoblastic lymphoma, order TLBLF / T-Lymphoblastic Leukemia/Lymphoma, FISH, Tissue. If a paraffin-embedded tissue sample is submitted for this test, testing will be canceled and TLBLF will be added and performed as the appropriate test.



Additional Testing Requirements


At diagnosis, conventional cytogenetic studies (CHRBM / Chromosome Analysis, Hematologic Disorders, Bone Marrow) and this fluorescence in situ hybridization (FISH) panel should be performed. If there is limited specimen available, only this test will be performed.



Shipping Instructions


Advise Express Mail or equivalent if not on courier service.



Necessary Information


A reason for testing and a flow cytometry and/or a bone marrow pathology report should be submitted with each specimen. The laboratory will not reject testing if this information is not provided; however, appropriate testing and interpretation may be compromised or delayed. If not provided, an appropriate indication for testing may be entered by Mayo Clinic Laboratories.



Specimen Required


Submit only 1 of the following specimens:

 

Preferred

Specimen Type: Bone marrow

Container/Tube:

Preferred: Yellow top (ACD)

Acceptable: Green top (heparin) or lavender top (EDTA)

Specimen Volume: 2 to 3 mL

Collection Instructions:

1. It is preferable to send the first aspirate from the bone marrow collection.

2. Invert several times to mix bone marrow.

3. Send bone marrow specimen in original tube. Do not aliquot.

 

Acceptable

Specimen Type: Blood

Container/Tube:

Preferred: Yellow top (ACD)

Acceptable: Green top (heparin) or lavender top (EDTA)

Specimen Volume: 6 mL

Collection Instructions:

1. Invert several times to mix blood.

2. Send whole blood specimen in original tube. Do not aliquot.


Forms

If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.

Secondary ID

609557

Useful For

Detecting a neoplastic clone associated with the common chromosome abnormalities and classic rearrangements observed in adult patients with T-cell acute lymphoblastic leukemia (T-ALL)

 

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

 

Evaluating specimens in which standard cytogenetic analysis is unsuccessful

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
TALAB Probe, Each Additional (TALAF) No, (Bill Only) No

Testing Algorithm

This test includes a charge for the probe application, analysis, and professional interpretation of results for 10 probe sets (20 individual fluorescence in situ hybridization [FISH] probes). Additional charges will be incurred for all reflex or additional probe sets performed.

 

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.

 

The diagnostic adult T-cell acute lymphoblastic leukemia (T-ALL) FISH panel includes testing for the following abnormalities using the following FISH probes:

9p24.1 rearrangement, JAK2 break-apart

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

11q23 rearrangement, MLL (KMT2A) break-apart

1p33 rearrangement, TAL1/STIL

t(5;14), TLX3/BCL11B fusion

7q34 rearrangement, TRB break-apart

14q11.2 rearrangement, TRAD break-apart

t(10;11), MLLT10/PICALM fusion

9q34 rearrangement, ABL1 break-apart

5q32 rearrangement, PDGFRB break-apart

 

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(AFDN)/MLL

t(9;11)(p22;q23) MLLT3/MLL

t(10;11)(p12;q23) MLLT10/MLL

t(11;19)(q23;p13.1) MLL/ELL

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(10;14)(q24;q11.2) TLX1/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/TLX1 or t(7;11)(q34;p13) TRB/LMO2.

 

For more information see Acute Leukemias of Ambiguous Lineage Testing Algorithm.

Method Name

Fluorescence In Situ Hybridization (FISH)

Reporting Name

Adult ALL (T-cell), FISH

Specimen Type

Varies

Specimen Minimum Volume

Blood: 2 mL
Bone Marrow: 1 mL

Specimen Stability Information

Specimen Type Temperature Time
Varies Ambient (preferred)
  Refrigerated 

Clinical Information

T-cell acute lymphoblastic leukemia (T-ALL) accounts for approximately 25% of cases of adult lymphoblastic leukemia. Specific genetic abnormalities are identified in most cases of T-ALL, although many of the classic abnormalities are "cryptic" by conventional chromosome studies and must be identified by fluorescence in situ hybridization (FISH) studies. Each of the genetic subgroups is important to detect and can be critical prognostic markers.

 

A combination of cytogenetic and FISH testing is currently recommended in all pediatric and adult patients to characterize the T-ALL clone for the prognostic genetic subgroups. A summary of the characteristic chromosome abnormalities identified in T-ALL is listed in the following table.

 

Table. Common Chromosome Abnormalities in T-cell Acute Lymphoblastic Leukemia

Cytogenetic change

Genes involved

del(1p33)

TAL1/STIL

t(5;14)(q35;q32)

TLX3/BCL11B

t(5q32;var)

PDGFRB

t(10;11)(p12;q14)

MLLT10/PICALM

Episomal amplification

ABL1

t(11q23;var)

MLL(KMT2A)

t(4;11)(q21;q23)

AFF1/MLL(KMT2A)

t(6;11)(q27;q23)

MLLT4(AFDN)/MLL(KMT2A)

t(9;11)(p22;q23)

MLLT3/MLL(KMT2A)

t(10;11)(p12;q23)

MLLT10)/MLL(KMT2A)

t(11;19)(q23;p13.1)

MLL(KMT2A)/ELL

t(11;19)(q23;p13.3)

MLL(KMT2A)/MLLT1

t(7q34;var)

TRB

t(7;10)(q34;q24)

TRB/TLX1

t(7;11)(q34;p13)

TRB/LMO2

t(14q11.2;var)

TRAD

t(10;14)(q24;q11.2)

TLX1/TRAD

t(11;14)(p13;q11.2)

LMO2/TRAD

t(9p24.1;var)

JAK2

t(9q34;var)

ABL1

Complex karyotype (≥4 abnormalities)

 

Reference Values

An interpretive report will be provided.

Cautions

This test is not approved by the US Food and Drug Administration, and it is best used as an adjunct to clinical and pathologic information.

 

Fluorescence in situ hybridization (FISH) is not a substitute for conventional chromosome studies because the latter detects chromosome abnormalities associated with other hematological disorders that would go undetected by this FISH panel test.

 

Bone marrow is the preferred specimen type for this FISH test. If bone marrow is not available, a blood specimen may be used if there are neoplastic cells in the blood specimen (as verified by a hematopathologist).

Day(s) Performed

Monday through Friday

Report Available

7 to 10 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

88271x20, 88275x10, 88291x1-FISH Probe, Analysis, Interpretation; 10 probe sets

88271x2, 88275x1-FISH Probe, Analysis; each additional probe set (if appropriate)

NY State Approved

Yes