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Test Code TALMF T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), Specified FISH, Varies


Ordering Guidance


This test is intended for instances when limited T-cell acute lymphoblastic leukemia (ALL) fluorescence in situ hybridization (FISH) probes are needed. The FISH probes to be analyzed must be specified on the ordering request. If specific probes are not included with this test request, testing will be delayed and may be canceled and automatically reordered by the laboratory as TALAF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), FISH, Adult, Varies or TALPF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), FISH, Pediatric, Varies depending on the age of the patient.

 

If a complete T-cell ALL FISH panel is preferred for an adult patient who is 31 years or older, order TALAF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), FISH, Adult, Varies.

 

If a complete T-cell ALL FISH panel is preferred for a pediatric patient who is 30 years or younger, order 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 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-lymphoblastic leukemia/lymphoma (T-LBL), order TLBLF / T-Cell Lymphoblastic Leukemia/Lymphoma, FISH, Tissue. If a paraffin-embedded tissue sample is submitted for this test, this test 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 a complete TALAF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), FISH, Adult, Varies or TALPF / T-Cell Acute Lymphoblastic Leukemia/Lymphoma (ALL), FISH, Pediatric, Varies should be performed, depending on patient's age. If there is limited specimen available, only fluorescence in situ hybridization testing will be performed.



Shipping Instructions


Advise Express Mail or equivalent if not on courier service.



Necessary Information


1. A list of probes requested for analysis is required. Probes available for this test are listed in the Testing Algorithm section.

2. A reason for testing must be provided. If this information is not provided, an appropriate indication for testing may be entered by Mayo Clinic Laboratories.

3. 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, but appropriate testing and interpretation may be compromised or delayed.



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: Whole 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.


Useful For

Detecting recurrent common chromosome abnormalities associated with T-cell acute lymphoblastic leukemia/lymphoma (T-ALL) using client-specified probes

 

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

 

Evaluating specimens in which standard cytogenetic studies are unsuccessful

 

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

Method Name

Fluorescence In Situ Hybridization (FISH)

Reporting Name

ALL (T-cell), Specified FISH

Specimen Type

Varies

Specimen Minimum Volume

Bone marrow: 1 mL; Whole blood: 2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Varies Ambient (preferred)
  Refrigerated 

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

Clinical Information

Acute lymphoblastic leukemia (ALL) accounts for approximately 70% of all childhood leukemia cases (ages 0 to 19 years), making it the most common childhood cancer.

 

Approximately 85% of pediatric cases of ALL are of B-cell lineage (B-ALL) and 15% are of T-cell lineage (T-ALL). T-ALL is more common in adolescents than younger children and accounts for 25% of adult ALL. When occurring as a primary lymphoblastic lymphoma (LBL), approximately 90% are T-cell lineage versus only 10% B-cell lineage. T-LBL often present as a mediastinal mass in younger patients, with or without concurrent bone marrow involvement.

 

An abnormal karyotype is found in 50% to 70% of T-ALL cases, although many of the classic abnormalities are "cryptic" by conventional chromosome studies and must be identified by fluorescence in situ hybridization (FISH) studies and are associated with various prognoses. One predictive marker, amplification of the ABL1 gene region, has been identified in 5% of T-ALL, and these patients may be responsive to targeted tyrosine kinase inhibitors.

 

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)(p13;q14)

MLLT10/PICALM

Episomal amplification

ABL1

del(9p)

CDKN2A(p16)

t(9p24.1;var)

JAK2

t(9q34;var)

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)(p13;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(6;7)(q23;q34)

MYB/TRB

t(7;10)(q34;q24)

TRB/TLX1

t(7;11)(q34;p15)

TRB/LMO1

t(7;11)(q34;p13)

TRB/LMO2

t(14q11.2;var)

TRAD

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

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

LMO2/TRAD

del(17p)

TP53

Complex karyotype (≥4 abnormalities)

 

Reference Values

An interpretive report will be provided.

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

88271x2, 88275x1, 88291x1-FISH Probe, Analysis, Interpretation; 1 probe set

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

Reflex Tests

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

Forms

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