FISH B-cell Lymphoma Panel

Fluorescence In Situ Hybridization – B-cell Lymphoma Panel

Test Overview

CPT Code(s)

88237-52, 88271×3, 88275, 88291

Methodology

Culture/Hybridization/Microscopy/Interpretation

Specimen Requirement

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 35o

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

B-cell lymphoma is a large group of heterogenous disorders and comprises a majority of non-Hodgkin lymphomas.  The most common abnormality seen in these disorders is the IGH gene translocations or rearrangements involving the 14q32 locus.  Included in this group is follicular lymphoma (FL), Burkitt Lymphoma (BL) and diffuse large B-cell lymphoma (DLBCL).  The characteristic chromosome abnormality, t(14;18) resulting in IGH/BCL2 fusion is seen in about 80% of FL, and about 20-30% of DLBCL while a majority of patients with BL harbor the characteristic t(8;14) resulting in cMYC/IGH fusion.  BCL6 gene rearrangements are also associated with B-cell lymphoma. Cyclin D1 gene rearrangements, especially the t(11;14) distinguishes mantle cell lymphoma (ML) from other lymphoproliferative disorders and hence is diagnostic for ML. Although majority of such abnormalities can be detected on routine chromosome analysis, interphase FISH analysis due to its high sensitivity can detect low-level clones thus identifying prognostically and therapeutically important genetic abnormalities.

Methods

The samples are usually cultured for 24-hours before hybridizing with the probes.  After hybridization and post-hybridization washes, the slides are analyzed under 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 B-cell lymphoma panel includes the following probes.

t(14;18)IGH / BCL2Cytocell (cat # LPH018)
8q rearrangementcMYCCytocell (cat # LPH010)
3q rearrangementBCL6Cytocell (cat # LPH035)
t(11;14)CCND1 / IGHCytocell (cat # LPH021)

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.