FISH T-cell Lymphoma

Fluorescence In Situ Hybridization – T-cell Lymphoma Panel

Test Overview

CPT Code(s)

88237-52, 88271×3, 88275, 88291

Methodology

Culture/Hybridization/Microscopy/Interpretation

Specimen Requirements

Bone Marrow and/or Leukemia BloodLymph Node
Container: Sodium Heparin (green top tube)Container: Transport Media/Saline
Optimal Quantity: 2-3 mlOptimal Quantity: 23 cm
Minimum Quantity: 1-2 mlMinimum Quantity: 13 cm
Storage: Room TemperatureStorage: Room Temperature
Stability at Room Temperature: 8 hours, then refrigerateStability at Room Temperature: 8 hours, then refrigerate
Transportation: Avoid freezing or heating over 35oCTransportation: Avoid freezing or heating over 35oC

Turnaround Time

Final report in 5 days for 90% cases

Test Details

Clinical Significance

Fluorescence in situ hybridization (FISH) is a sensitive method to detect smaller genomic changes associated with various hematological malignancies and solid tumors.  There are several advantages with FISH technology over routine chromosome analysis and such advantages include the ability of FISH technology to detect genomic abnormalities in non-viable and non-dividing tissues, rapid turnaround time, and increased resolution.  However, FISH technology is complementary to routine chromosome analysis and cannot substitute routine chromosome analysis for diagnosis of cancer.

Clinical Background

The common genomic abnormalities seen in T-cell lymphoma usually involve the T-cell receptor genes (TCR) with various transcription factors.  The genes that are commonly involved are TCR-alpha (TCRA) and TCR-delta (TCRD) at 14q11, TCR-beta (TCRB) at 7q35, TCR-gamma (TCRG) at 7p15.  The ALK gene rearrangements occur in about 2% of adults and 13% of children.

Methods

The samples are usually cultured for 24-hours before hybridizing with the probes.  After hybridization and post-hybridization washes, the slides are analyzed using a fluorescence microscope equipped with epifluorescence and appropriate filter sets.  Analysis and scoring is carried out by two certified technologists in a blinded fashion.  Results are reviewed by both the laboratory manager and the director.  The T-cell lymphoma FISH panel includes the following probes.

inv(7) / iso(7q) TCRB Cytocell (cat # LPH048)
inv(14) / 14q rearrangement TCRAD Cytocell (cat # LPH047)
t(2;5) / 2p rearrangement ALK Cytocell (cat # LPS 019)

 Interpretation of Results

The morphologic interpretation and correlation of results on all cases is performed by a board-certified doctoral level scientist (laboratory director). The final report has a narrative description of results.  If abnormalities are present, they are explained in a paragraph which helps to clarify and correlate chromosomal findings with phenotype. References are included in the report to help the referring physician with interpretation, which include books or journals that contain appropriate information. Recommendations are made as to any additional testing, if necessary.