Test ID: TLPF    
T-Cell Lymphoma, FISH, Varies

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

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

This test includes a charge for application of the first probe set (2 FISH probes) and professional interpretation of results. Additional charges will be incurred for all reflex probes 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.

When this test and flow cytometry testing for leukemia/lymphoma are ordered concurrently, the flow cytometry result will be utilized to determine if sufficient clonal T-cells are available for FISH testing. If the result does not identify a sufficient clonal T-cell population, this FISH test order will be canceled and no charges will be incurred.

If FISH testing proceeds, probes will be performed based on the lymphoma subtype suspected/identified utilizing the table located in Clinical Information.

If the patient is being tracked for known abnormalities, indicate which probes should be used.

The following probe sets are available within the T-cell lymphoma FISH profile:

14q32.1 rearrangement, TCL1A

/i(7q)/ -7/7q-, D7S486/D7Z1

+8, D8Z2/MYC

If T-cell prolymphocytic leukemia/lymphoma (T-PLL) is indicated, TCL1A rearrangement is performed, with reflex to the TRAD FISH probe if TCL1A is negative,

See Bone Marrow Staging for Known or Suspected Malignant Lymphoma Algorithm in Special Instructions.

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.

There are a few common chromosome abnormalities associated with specific T-cell lymphoma subtypes evaluated by this FISH test, as follows:

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

An interpretive report will be provided.

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 abnormality detected may help subtype the neoplasm.

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

This test is not approved by the U.S. Food and Drug Administration and it is best used as an adjunct to existing clinical and pathologic information.

Bone marrow is the preferred sample type for this FISH test. If bone marrow is not available, a blood specimen may be used if there are malignant cells in the blood specimen (as verified by hematopathology).

Each probe was independently tested on a set of normal bone marrow control samples, and when available bone marrow samples from patients diagnosed with a T-cell lymphoma. Normal cutoffs were calculated based on the results from 25 normal specimens. Each probe set was evaluated to confirm the probe set detected the abnormality it was designed to detect.

1. WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues. Edited by SH Swerdlow, et al. IARC, Lyon 2017

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

• Bone Marrow Staging for Known or Suspected Malignant Lymphoma Algorithm