T-Cell Lymphoma, FISH, Tissue
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
T-cell malignancies account 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 extrandodal lymphoma subtypes. The 2 most prevalent lymphoma subtypes are unspecified peripheral T-cell lymphoma (3.7%) and ALCL (2.4%).
A few common chromosome abnormalities are associated with specific T-cell lymphoma subtypes, including:
-inv (14)(q11q32) and t(14;14)(q11;q32) involving the T-cell leukemia/lymphoma 1 gene (TCL1A) at 14Q32
-Translocations involving the ALK gene at 2p23 in ALCL
-Isochromosome 7q and trisomy 8 in hepatosplenic T-cell lymphoma
T-ALL is a neoplastic disorder of lymphoblasts committed to the T-cell lineage. These malignancies comprise 15% to 20% of acute leukemias. While half of T-ALL patients have normal chromosome studies, molecular cytogenetic analysis can identify abnormalities including:
These abnormalities may be seen in tissues (ie, lymph nodes), as well as in blood and bone marrow.
This tissue-based assay detects the common chromosome abnormalities observed in T-cell lymphoma and T-ALL (for blood and bone marrow in patients with T-ALL, see FRTAL / T-Cell Acute Lymphoblastic Leukemia [T-ALL], FISH; for all other T-cell lymphomas, see FRTLP / T-Cell Lymphoma, FISH, Blood or Bone Marrow). These probes have diagnostic relevance and can also be used to track response to therapy.
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 neoplasms
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 is supportive of a diagnosis of a T-cell lymphoma or T-cell acute lymphoblastic leukemia. The specific anomaly detected may help subtype the neoplasm.
The absence of an abnormal clone does not rule out the presence of a neoplastic disorder.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
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 Health Organization Classification of Tumours. Pathology and Genetics of Tumours of aematopoietic 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
4. Graux C, Cools J, Michaux L, et al: Cytogenetics and molecular genetics of T-cell acute lymphoblastic leukemia: from thymocyte to lymphoblast. Leukemia 2006;20:1496-1510
5. Cayuela JM, Madani A, Sanhes L, et al: Multiple tumor-suppressor gene 1 inactivation is the most frequent genetic in T-cell lymphoblastic leukemia. Blood 1996;87:3180-3186