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Interpretive Handbook

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Test 89040 :
T-Cell Lymphoma, FISH, Blood or Bone Marrow

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

T-cell neoplasms are relatively uncommon, accounting for approximately 12% of all non-Hodgkin lymphomas. There are several subtypes of T-cell neoplasms: T-cell acute lymphoblastic leukemia (T-ALL), T-cell prolymphocytic leukemia (T-PLL), T-cell large granular lymphocytic leukemia (T-LGL), anaplastic large cell lymphoma (ALCL), peripheral T-cell lymphoma, and various other cutaneous, nodal, and extranodal lymphoma subtypes. The 2 most prevalent lymphoma subtypes are unspecified peripheral T-cell lymphoma (3.7%) and ALCL (2.4%). T-cell neoplasms are among the most aggressive of all hematologic and lymphoid neoplasms with the exception of ALCL, which is usually responsive to chemotherapy.

 

There are a few common chromosome anomalies associated with specific subtypes, which this FISH test can detect:

-inv(14)(q11q32) and t(14;14)(q11;q32), which involve the T-cell leukemia/lymphoma 1 gene (TCL1A) and have been associated with T-PLL

-Isochromosome 7q and trisomy 8, which have been associated with hepatosplenic T-cell lymphoma

 

These probes have diagnostic relevance and can also be used to track response to therapy.

 

This assay detects chromosome abnormalities observed in the blood and bone marrow of patients with T-cell lymphoma (for patients with T-cell acute leukemia, see FRTAL / T-Cell Acute Lymphoblastic Leukemia [T-ALL], FISH).

Useful For Suggests clinical disorders or settings where the test may be helpful

Detecting a neoplastic clone associated with the common chromosome anomalies seen in patients with various T-cell lymphomas 

 

Tracking known chromosome anomalies and response to therapy in patients with T-cell lymphoma

Interpretation Provides information to assist in interpretation of the test results

A neoplastic clone is detected when the percent of cells with an abnormality exceeds the normal reference range for any given probe.

 

Detection of an abnormal clone supports a diagnosis of a T-cell lymphoma. The specific anomaly detected may help subtype the neoplasm.

 

The absence of an abnormal clone does not rule out the presence of neoplastic disorder.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test should not be ordered on patients with T-cell acute lymphoblastic leukemia. In these situations, see FRTAL / T-Cell Acute Lymphoblastic Leukemia (T-ALL), FISH.

 

This test is not FDA-approved; and it is best used as an adjunct to existing clinical and pathologic information.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. World Heath Organization Classification of Tumours. Pathology and Genetics of Tumours of Haematopoietic and Lymphoid Tissues. Edited by ES Jaffe, NL Harris, H Stein, JW Vardiman. Lyon, IARC Press, 2001

2. Gesk S, Martin-Subero JI, Harder L, et al: Molecular cytogenetic detection of chromosomal breakpoints in T-cell receptor gene loci. Leukemia 2003;17:738-745

3. Chin M, Mugishima H, Takamura M, et al: Hemophagocytic syndrome and hepatosplenic (gamma)(delta) T-cell lymphoma with isochromosome 7q and 8 trisomy. J Pediatr Hematol Oncol 2004;26(6):375-378


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