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HelpTest ID TLBLF T-Lymphoblastic Leukemia/Lymphoma, FISH, Tissue
Ordering Guidance
This test does not include a pathology consultation. If a pathology consultation is requested, order PATHC / Pathology Consultation, and appropriate testing will be added at the discretion of the pathologist and performed at an additional charge.
Mayo Hematopathology Consultants are involved in both the pre-analytic (tissue adequacy and probe selection, when applicable) and post-analytic (interpretation of fluorescence in situ hybridization [FISH] results in context of specific case, when applicable) phases.
This assay detects chromosome abnormalities observed in paraffin-embedded tissue samples of patients with T-lymphoblastic leukemia/lymphoma (T-LBL). If a non-paraffin embedded bone marrow or blood sample is received for this test, the test will 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.
Shipping Instructions
Advise Express Mail or equivalent if not on courier service.
Necessary Information
1. A pathology report is required for testing to be performed. If not provided, appropriate testing and/or interpretation may be compromised or delayed. Acceptable pathology reports include working drafts, preliminary pathology, or surgical pathology reports.
2. The following information must be included in the report provided:
-Patient name
-Block number - must be on all blocks, slides, and paperwork
-Date of collection
-Tissue source
3. 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.
4. A list of probes is required if select probes are necessary or if the patient is being tracked for known abnormalities. See Table in Clinical Information.
Specimen Required
Submit only 1 of the following specimens:
Preferred:
Specimen Type: Tissue block
Collection Instructions: Submit a formalin-fixed, paraffin-embedded tumor tissue block. Blocks prepared with alternative fixation methods will be attempted but are less favorable for successful results; provide fixation method used.
Additional Information:
1. Paraffin embedded specimens can be from any anatomic location (skin, soft tissue, lymph node, etc).
2. Bone specimens that have been decalcified will be attempted for testing, but the success rate is approximately 50%.
Acceptable:
Specimen Type: Tissue slides
Slides: 1 Hematoxylin and eosin stained and 2 unstained for each probe set
Collection Instructions:
1. Include 1 hematoxylin and eosin-stained slide for the entire test order.
2. For each probe set ordered, 2 consecutive, unstained, 5 micron-thick sections placed on positively charged slides
Useful For
Detecting recurrent common chromosome abnormalities associated with T-cell acute lymphoblastic leukemia/lymphoma (T-ALL) using client specified probes
Identifying and tracking known chromosome abnormalities in patients with T-ALL and monitoring response to therapy
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| _I300 | Interphases, >=100 | No | No |
| _I099 | Interphases, 25-99 | No | No |
| _IL25 | Interphases, <25 | No | No |
| _PB03 | Probe, +3 | No | No |
| _PB02 | Probe, +2 | No | No |
| _PADD | Probe, +1 | No | No |
| _PBCT | Probe, +2 | No | No |
Testing Algorithm
This test may be ordered in 2 distinct ways allowing different combinations of probes to be utilized based on the clinical question, including the standard (diagnostic) T-lymphoblastic leukemia/lymphoma (TLBL) fluorescence in situ hybridization (FISH) panel and the individual TLBL fluorescence in situ hybridization (FISH) probes (per client request).
This test includes a charge for the probe application, analysis, and professional interpretation of results for one probe set (2 individual [FISH] probes). Additional charges will be incurred for all reflex or additional probe sets 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.
If individual TLBL FISH probes are wanted, the specific probes requested must be noted on the request form or in the reason for referral. If no FISH probes are indicated, the standard (diagnostic) panel will be performed.
The standard (diagnostic) panel includes testing for the following abnormalities, using the FISH probes listed:
1p33 rearrangement or STIL deletion, request probe TAL1/STIL
t(5;14)(q35;q32) or TLX3::BCL11B fusion, request probe TLX3/BCL11B
t(7q34;var) or 7q34 rearrangement, request probe TRB break-apart
+9/9p-, request probe CDKN2A/D9Z1
t(9;22) or ABL1 amplification, request probe ABL1/BCR
t(10;11)(p12;q14) or MLLT10::PICALM fusion, request probe MLLT10/PICALM
t(11q23;var) or 11q23 rearrangement, request probe MLL(KMT2A) break-apart
t(14q11.2;var) or 14q11.2 rearrangement, request probe TRAD break-apart
-17/17p-, request probe TP53/D17Z1
When an MLL(KMT2A) rearrangement is identified, appropriate reflex testing will be performed with 1 or more dual-fusion (D-FISH) probe sets in an attempt to identify the translocation partner.
Reflex testing is performed for the following abnormalities, using the FISH probes listed:
t(4;11)(q21;q23) or AFF1::MLL(KMT2A) fusion, request probe AFF1/MLL
t(6;11)(q27;q23) or MLLT4(AFDN)::MLL(KMT2A) fusion, request probe MLLT4(AFDN)/MLL
t(9;11)(p22;q23) or MLLT3::MLL(KMT2A) fusion, request probe MLLT3/MLL
t(10;11)(p12;q23) or MLLT10::MLL(KMT2A) fusion, request probe MLLT10/MLL
t(11;19)(q23;p13.1) or MLL(KMT2A)::ELL fusion, request probe MLL/ELL
t(11;19)(q23;p13.3) or MLL(KMT2A)::MLLT1 fusion, request probe MLL/MLLT1
When a TRB(TCR beta) rearrangement is identified, reflex testing will be performed with the D-FISH probe set for t(7;10)(q34;q24) TRB::TLX1 fusion in an attempt to identify the translocation partner. To request this probe specifically, request probe TRB/TLX1.
When a TRAD(TCR alpha delta) rearrangement is identified, reflex testing will be performed with the D-FISH probe set for t(10;14)(q24;q11.2) TLX1::TRAD fusion in an attempt to identify the translocation partner. To request this probe specifically, request probe TLX1/TRAD.
Appropriate ancillary probes may be performed at consultant discretion to render comprehensive assessment. Any additional probes will have the results included within the final report and will be performed at an additional charge.
Method Name
Fluorescence In Situ Hybridization (FISH)
Reporting Name
T-Lymphoblastic Leuk/Lymph, FISH,TsSpecimen Type
TissueSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Tissue | Ambient (preferred) | |
| Refrigerated | ||
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
T-lymphoblastic lymphoma (T-LBL) is the non-leukemic form of T-acute lymphoblastic leukemia (T-ALL). In the United States, the incidence of ALL is roughly 6000 new cases per year, or approximately 1 in 50,000. 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 ALL cases are B-cell lineage (B-ALL) and 15% are 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, approximately 90% are T-cell lineage versus only 10% B-cell lineage. T-LBL characteristically presents in adolescents and young adults as a mediastinal mass with or without concurrent bone marrow involvement. It is not uncommon that the only sample available with T-LBL involvement is a paraffin-embedded mediastinal or lymph node biopsy specimen.
Specific genetic abnormalities can be identified in the majority of T-ALL/LBL 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/LBL, and these patients may be responsive to targeted tyrosine kinase inhibitors. A combination of cytogenetic and FISH testing is currently recommended in all pediatric and adult patients to characterize the T-ALL/LBL clone for prognostic genetic subgroups.
Reference Values
An interpretive report will be provided.
Interpretation
A neoplastic clone is detected when the percent of cells with an abnormality exceeds the normal reference range for any given probe set.
A positive result is not diagnostic for T-lymphoblastic lymphoma (T-LBL) but may provide relevant prognostic information.
The absence of an abnormal clone does not rule out the presence of a neoplastic disorder.
Cautions
This test is not approved by the US Food and Drug Administration and is best used as an adjunct to existing clinical and pathologic information.
Fixatives other than formalin (eg, Prefer, Bouin's) may not be successful for fluorescence in situ hybridization (FISH) assays. Non-formalin fixed specimens will not be rejected.
Paraffin-embedded tissues that have been decalcified will be attempted but may not be successful for FISH analysis. The success rate of FISH studies on decalcified tissue is approximately 50%.
Fluorescent in situ hybridization studies will be attempted if sufficient tumor is present for analysis. The pathologist reviewing the hematoxylin and eosin-stained slide may find it necessary to cancel testing if insufficient tissue/tumor is available for testing.
If no FISH signals are observed post-hybridization, the case will be released indicating a lack of FISH results.
Clinical Reference
WHO Classification of Tumours Editorial Board, eds. Haematolymphoid tumours. 5th ed. IARC Press; 2024. WHO Classification of Tumours, Volume 11
Method Description
This test uses fluorescence in situ hybridization (FISH) enumeration strategy probes to detect deletions of CDKN2A on chromosome 9p and TP53 on chromosome 17p. Dual-color, break-apart (BAP) probes are used to detect rearrangements of the TAL1/STIL(SIL), TRB(TCR beta), MLL(KMT2A), and TRAD(TCR alpha delta) locus on 1p33, 7q34, 11q23, and 14q11.2, respectively. Dual-color, dual-fusion strategy (D-FISH) probe sets are used to detect fusion of the TLX3(HOX11L2)/BCL11B, ABL1(ABL)/BCR, and MLLT10/PICALM locus on (5;14)(q35;q32), (9;22)(q34;q11.2), and (10;11)(p12;q14) respectively. D-FISH probe sets are also used in reflex testing when rearrangements of MLL(KMT2A), TRAD(TCR alpha delta) and TRB(TCR beta) gene loci are detected. Amplification of the ABL1 gene is detected using a D-FISH probe strategy. Paraffin-embedded tissues are cut at 5 microns and mounted on positively charged glass slides. The selection of tissue and the identification of target areas on the hematoxylin and eosin (H and E) stained slide are performed by a pathologist. Using the H and E-stained slide as a reference, target areas are etched with a diamond-tipped etcher on the back of the unstained slide to be assayed. For each probe set, the probes are hybridized to the appropriate target areas and 2 technologists each analyze 50 interphase nuclei (100 total) per probe set with the results expressed as the percent abnormal nuclei.(Unpublished Mayo method)
Day(s) Performed
Monday through Friday
Report Available
7 to 10 daysTest 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
88271 x 2, 88291-DNA probe, each (first probe set), Interpretation and report
88271 x 2-DNA probe, each; each additional probe set (if appropriate)
88271-DNA probe, each; coverage for sets containing 3 probes (if appropriate)
88271 x 2-DNA probe, each; coverage for sets containing 4 probes (if appropriate)
88271 x 3-DNA probe, each; coverage for sets containing 5 probes (if appropriate)
88274 w/modifier 52-Interphase in situ hybridization, <25 cells, each probe set (if appropriate)
88274-Interphase in situ hybridization, 25 to 99 cells, each probe set (if appropriate)
88275-Interphase in situ hybridization, 100 to 300 cells, each probe set (if appropriate)
NY State Approved
YesForms
If not ordering electronically, complete, print, and send 1 of the following forms with the specimen: